עבודה זו נתמכה על ידי המעבדה מחקר צבא ארה ב, Adelphi, MD, ארצות הברית, תחת גרנט W91ZLK-12-P-0447. המדידות תהודה נערכו עם העזרה של מיכאל אבן, אנתוני ברוק. המדידה מצלמות תרמיות נערך בעזרת דיימון Conover מאוניברסיטת וושינגטון ג'ורג '.

1. בחירה ועיצוב מבנה של האופטימלית
<ol><li>בחר את קרן קבועה-קבוע עבור כוונון תדירות מגוון רחב (לעומת מועמדים אחרים, זה מאפשר מגוון רחב כוונון כאשר הוא מחומם עקב שלה מקדם טמפרטורה גדול של תדר (TCF), הרחבה תרמי זניח קבוע).</li>
	<li>עיצוב קרן יותר אם המטרה היא כוונון שיפור יעילות. עיצוב קרן קצרה יותר אם המטרה היא תדירות מקפץ או אותות יישומי מעקב.</li>
</ol>2. מידול פבריקציה משלימים תחמוצת מתכת מוליכים למחצה (CMOS)
<ol><li>עיצוב וליצור דגם תלת-ממד עבור מסנן MEMS בתוכנית מבוססי FEM.</li>
	<li>לשחזר באותה הפריסה בכלי העיצוב מעגל משולב (IC), שכבה אחרי שכבה כדי ליצור את הקובץ gds.</li>
	<li>שלח קובץ זה gds לבית היציקה CMOS עבור ייצור (השתמשנו טכנולוגיית CMOS מיקרומטר 0.6).</li>
	<li>להמשיך עם עיבוד שלאחר סיום תהליך ה-CMOS (שים לב שיש האסימונים שכבות polysilicon, אלומיניום אוקסיד).<ol>
<li>התנהגות /O32 CHF יבש לחרוט תהליך דרך פלזמה inductively בשילוב (ICP) לחרוט המערכת. לחרוט את SiO2 בין שכבות אלומיניום ויוצרים את הקורות על יחס הגובה-רוחב של 5.7. במשך תהליך זה, השתמש בפרמטרים הבאים: CHF3 40 sccm, O2 -5 sccm, לחץ על 0.5 הרשות הפלסטינית, ICP כוח-500 W וכוח מדגם ב-100 W עם הסכום הכולל 56 דקות לחרוט זמן.</li>
		<li>להחיל את XeF2 לחרוט בתהליך המצע סיליקון כדי ליצור חלל עומק מיקרומטר 9 תחת הקורות. עבור תהליך זה, השתמש XeF2 תצריב המערכת עבור 3 מחזורים-3T, s 60/מחזור.</li>
	</ol>
</li>
	<li>לאפיין את ההתקנים עם מיקרוסקופ אלקטרונים סריקה (SEM) כדי להבטיח שהם מיוצרים כהלכה. בשלב זה, לשנות את קרן האצת מתח כדי 2.58 kV ואת המרחק לעבוד עד 9.5 מ"מ.</li>
</ol>3. מכשיר בדיקה
הערה: התקן בדיקות מורכבות צעדים רבים כולל את ג'ול חימום מבחן, מבחן תגובת תדר.
<ol><li>
מצלמות תרמיות לבדיקת מחממי מוטבע
	<ol>
<li>מקם את המצלמה הטרמית על גבי השבב ובדוק את מחממי מוטבע כדי להבטיח שהם מחממים את הקורות.</li>
		<li>לחבר את ספק הכוח על החבילה שבב ולהחיל מתח DC על תנורים מוטבע 0 V 5.7 V במרווחים קטנים כדי להגדיל את הטמפרטורה בכל הקורות.</li>
		<li>להקליט את פרופיל הטמפרטורה לאורך כל החבילה שבב באמצעות מצלמה תרמית במהלך תהליך חימום. לשמור את התוצאות בתוכנית מחשוב מספריים, להתוות את הפרופיל חימום.</li>
	</ol>
</li>
	<li>
. מכיילת את הכיוונון LDV ובדיקה
	<ol>
<li>הצב הלייזר על גבי הקורות ארוך 120 מיקרומטר.</li>
		<li>חיבור ספק הכוח בין הקורות ארוך 120 2 מיקרומטר להחלת הן 7 V DC מתח V AC 3 עבור הפעולה תהודה. להתחבר המתח הסטייה נוספים של DC מחממי מוטבעים עם מקסימום של 5.7 V להחיל ג'אול חימום הקורות במהלך פעולת תהודה.</li>
		<li>להעביר את הלייזר למקום אחר על הקורה להשיג השתקפות לייזר רעש נמוכה. ודא להגביר את עוצמת הפס הכחול כדי להקטין את הרעש.</li>
		<li>לחלק את המסך תצוגות מרובות כדי לכייל ולהתחיל את הכיוונון מדידה.</li>
		<li>עבור אל הגדרות רכישה, להגדיר את מצב המדידה FFT, לא להשתמש כלשהו המסנן, והגדר את רוחב הפס 2 מגה הרץ.</li>
		<li>לשנות את המהירות כך זה יכול לתמוך את התדר המרבי של 2.5 מגה-הרץ.</li>
		<li>השתמש waveform מעוצבנת תקופתיים. הערה: כאן, משרעת מסמלת מתח AC ואת היסט מסמלת מתח DC.</li>
		<li>להתחיל את המדידה עם תוכנית התקנה חדשה זו.</li>
		<li>עדכן את ההגדרות רכישה על-ידי שינוי המתח DC ל- 1 V.</li>
		<li>להפחית את המתח הסטייה יישומית בחלון הגדרות רכישה כאשר Ref1 מראה את האזעקה אדום (פירוש האות רועש).</li>
		<li>להעביר את הלייזר למקום אחר על הקורה להמשיך להגדיל את יחס אות לרעש. מדי פעם, ייתכן כתמים רע על הקורה הגורמת האזעקה אדום על הבר רטט; במקרה זה, להמשיך לחפש המקום הטוב ביותר.</li>
	</ol>
</li>
	<li>
בדיקות 68 מיקרומטר ארוך MEMS מסננים דרך LDV
	<ol>
<li>בחר המסנן MEMS ארוך מיקרומטר 68 לבדיקה.</li>
		<li>החל 25 מתח V DC מתח V AC 5 ביחד בין הקורות זמן סמוכים 68 2 מיקרומטר. . כאן, מתח DC מספק כיפוף ומאפשר מתח AC הפעולה תהודה.</li>
		<li>חלות של מתח DC נוספים מחממי מוטבעים בקרן ארוכה 68 מיקרומטר, תגביר את המתח בין 0 V כדי 5.7 V במרווחים קטנים. זה יספק תדירות כוונון בהתבסס על ג'ול חימום.</li>
		<li>להתבונן להקליט את תדר תהודה ואת שלב התגובה ביחס המתח הסטייה יישומית בכל שלב, לסכם את התוצאות בטבלה. כאן, תדירות הכולל כוונון עבור הדוגמה הוא בסביבות 874 kHz המתח V DC 5.7 מוחל על החימום מוטבעים. הערה: סימולציות (מצד ימין) ומדידה אמיתי (בצד שמאליים) מסונכרנים.</li>
	</ol>
</li>
	<li>
מדידה מצבי גבוה יותר
	<ol>
<li>לחץ על הכפתור A/D כדי לעבור חלון הגדרות רכישה הפגינו בסעיף 3.2, לשנות את המהירות כך יתמכו תדרים גבוהים מאוד.</li>
		<li>למדוד הראשון ולמצב השני עם השלב שלהם. הערה: העקירה תהודה הראשי בכיוון Y עבור מצב-1 וזה בכיוון Z (זה כלפי המיקרוסקופ) עבור מצב-2.</li>
	</ol>
</li>
</ol>4. הימנעות כשל בהתקן
<ol><li>
גל מרובע בתדר נמוך אות ליישום לפתור את stiction
	<ol>
<li>החל אות גל מרובע 1 הרץ כדי לפתור את הבעיה stiction הנובעת טעינה אלקטרוסטטית בין שתי הקורות סמוכים.</li>
		<li>עבור תיבת היסט ולהגדיר את מתח DC ל- 1 V, תוך שמירה על מתח AC-1 V.</li>
		<li>ללכת אל תיבת תדירות ולהגדיר את התדירות 1 הרץ.</li>
		<li>להפעיל וליישם תוכנית התקנה חדשה זו על הקורות.</li>
		<li>להתבונן בהפרדה בין הקורות.</li>
	</ol>
</li>
	<li>
עומס תרמי גבוה וצריבה
	<ol>
<li>דוגמה נוספת לשימוש במבחן הלחץ תרמי.</li>
		<li>. תגביר את המתח הסטייה שהוחלו על המזגן מוטבע במרווחים קטנים כדי למצוא את המתח המרבי המותר לפני ההתקן נכשל עקב עומס תרמי גבוה</li>
	</ol>
</li>
</ol>5. להגביר את יכולת כוונון
<ol><li>להחיל מתח V DC 25, 5 V AC מתח יחד בין הקורות סמוכים 68 2 מיקרומטר תוך הגדלת המתח הסטייה שהוחלו על המזגן מוטבע 0 V כדי 5.7 V, עבור משמרת 661 kHz בתדר הכולל.</li>
	<li>. תגביר את המתח הסטייה יישומית 25 V ל-35 V כדי להוסיף ל האביב נוספים מלחלח בין הקורות זמן סמוכים 68 2 מיקרומטר, תוך החלת מתח V AC 1 ולשמור את אותו סידור מתח הסטייה בתנור מוטבע</li>
	<li>להקליט השיפור 32% משמרת הכולל תדירות כמו זה צריך להגדיל מתוך 661 kHz ל kHz 875 בא באביב נוספים מלחלח ומרכך. הערה: לפי מיטב ידיעתנו, לשנות את יכולת כוונון כלי הנגינה MEMS הושגה לראשונה בעבודה זו.</li>
</ol>

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אין לנו לחשוף.

אחד השלבים הקריטיים בבניית MEMS מסננים הוא עיצוב המכשיר מבוסס על האזור יישום. הקרן צריך להיות ארוך יותר או דק יותר עבור כוונון יותר יעילות (עמודים לדקה/mW), אך קצר יותר או מדלל תדירות מקפץ או אות יישומי מעקב. באותו אופן, זיהוי האות ברור דרך LDV הינה קריטית במכשיר בדיקה ולכן עדיף לעצב את הקורה עם ע?...

יש ביקוש גובר והולך למסננים MEMS עקב שלהם אמינות גבוהה, צריכת חשמל נמוכה, העיצוב הקומפקטי, גורם באיכות גבוהה ועלות נמוכה. הם נמצאים בשימוש נרחב חיישנים וכן חלקי הליבה בתקשורת אלחוטית. חיישני טמפרטורה1,2,ביו-חיישנים3, חיישנים גז4, מסננים5,6,7ומתנדים הם האזורים היישום הפופולרי ביותר. המסננים MEMS אלקטרוסטטית הפופולריים ביותר הם קרן קבועה-קבוע5,8, שלוחה2, קולן6,6,קרן חינם-חינם7, עיצוב flexural-דיסק7, ו עיצוב צורה מרובע9.
ישנם שלבים קריטיים רבים במימוש מסנן MEMS, כגון עיצוב מתודולוגיה (מבנה המבוסס על יישום אופטימיזציה, תדירות מגוון רחב טווח כוונון, והימנעות כשלים) ואפיון (שטנץ מהירה, הימנעות טפיליות capacitances, וצורות גילוי גבוה יותר). תדירות כוונון יכולת נדרש כדי לפצות על כל שינוי תדירות טולרנסים פבריקציה נוספת, או וריאציות טמפרטורת הסביבה. טכניקות שונות10,11,12 דווחו בספרות כדי לטפל דרישה זו; עם זאת, יש להם מספר חסרונות כגון תדירות מוגבל כוונון יכולת, בתדר נמוך מרכזי, הודעה נוספת הדרישות ותהליכי חימום חיצוני10,11.
במחקר זה אנו מציגים מגוון רחב תדירות כוונון על ידי ג'אול חימום בשיטה5,13 מעל תדר מוגבל כוונון טווח באמצעות מודול הנפח שינוי12 (עולה המתח DC הסטייה בין שתי הקורות סמוכים) ו- a חומר שלב המעבר שיטת10,11. יתר על כן, הבחירה האופטימלית מבנה, עיצוב מבוסס יישומים היו סיכם Göktaş, מצעי13. כאן, אנו מראים כיצד לכוון את התדירות תהודה של קרן קבועה-קבוע על ידי הגדלת מתח DC שהוחל החימום מוטבעים עם העזרה של LDV... ההדמיה ניתוח (FEM) סופיים מסונכרן עם מדידה LDV באותה מסגרת בשביל להמחיש את מנגנון כוונון. זה כולל את ג'ול חימום וכיפוף פרופיל לאורך הקורה.
אנו מציגים גם את הכשלים אפשרי (שרוף והתקנים stiction) ופתרונות מוצעים שלהם. ג'ול חימום השיטה בשילוב עם הלחץ תרמית גבוהה של קרן קבועה-קבוע מספק מגוון רחב תדירות כוונון, אך באותו זמן יכול לגרום התקני שרוף ברמה טמפרטורה מסוימת. זו מיוחסת הלחץ תרמית גבוהה בין חומרים שונים14. הפתרון הוא להגביר את המתח DC בין הקורות סמוכים שני, אשר בתורו מגביר את טווח הכוונון (ב-32%), והוא מבטל את הצורך בטמפרטורה גבוהה. שיטה זו "כוונון הכוונון-הטווח" היה קודם הפגינו Göktaş, מצעי5, הסביר בפירוט רב יותר Göktaş, מצעי13, והציג מחדש כאן. Stiction, מצד שני, יכול להתרחש במהלך פעולת תהליך או תהודה פבריקציה נוספת. היו טכניקות רבות הציע כדי לטפל בבעיה זו כגון החלת ציפוי פני השטח כדי להפחית אדהזיה אנרגיה15,16, חספוס פני השטח גובר17ולאחר תהליך תיקון18לייזר. לעומת זאת, אנו מציגים טכניקה פשוטה אות גל מרובע בתדר נמוך היה מוחל בין שתי הקורות המצורפת ואיפה ההפרדה הוקלט בהצלחה על ידי LDV. בשיטה זו ניתן לשלול תוספת עלות ולהפחית את המורכבות עיצוב.
עוד צעד קריטי בבניית המדינה של אמנות MEMS מסנן הוא איפיון ואימות. אפיון עם מנתח רשת היא אחת השיטות הפופולריות ביותר והשימוש בהם נפוץ; עם זאת, יש מספר חסרונות. קיבול טפיל קטן אפילו יכול להרוג את האות ולכן זה דורש בדרך כלל6,8 3,מעגל מגבר לחיסול רעש, זה יכול לזהות רק הראשונה במצב תהודה. מצד שני, אפיון עם LDV הינה בחינם מבעיה זו קיבוליות טפילי, ניתן לזהות הרבה תזוזה קטנה יותר. פעולה זו מאפשרת שטנץ מהירה, תוך ביטול הצורך מגבר עיצוב. יתר על כן, LDV יכול לזהות תהודה גבוה יותר מצב של MEMS מסננים. תכונה זו הוא רב מאוד, במיוחד בתחום ביולוגיים רגישה מאוד. מצב זיז גבוה יותר יכול לספק רגישות הרבה יותר19. המדידה מצב גבוה יותר של קרן קבועה-קבוע עם LDV שמוצג וחלים פמ סימולציה מדידה. התוצאות מוקדמת של הסימולציה פמ מציעים שיפור עד 46 פעמים ב רגישות לעומת מצב הראשונה של קרן קבועה-קבוע.

<table><tbody><tr><td>Laser Doppler Vibrometer</td><td>Polytec</td><td>Polytec MSA-500</td><td></td></tr><tr><td>Scanning Electron Microscope</td><td>Zeiss</td><td></td><td></td></tr><tr><td>Thermal Camera</td><td>X</td><td></td><td></td></tr><tr><td>Power Supply&amp;nbsp;</td><td>Egilent</td><td>(E3631A)</td><td></td></tr><tr><td>Microscope</td><td>X</td><td></td><td></td></tr><tr><td>Coventor</td><td>Coventor</td><td></td><td>Simulation Tool</td></tr><tr><td>Cadence Virtuoso</td><td>Cadence</td><td></td><td>Simulation Tool</td></tr><tr><td>Multisim</td><td>Multisim</td><td></td><td>Simulation Tool</td></tr></tbody></table>

design and characterization methodology for efficient wide range tunable mems filters

. הנה, נדגים את היתרונות לייזר דופלר ממדי רטט (LDV) טכניקות שגרתיות (מנתח רשת), כמו גם טכניקות כדי ליצור מסנן מערכות (MEMS) המבוססת על יישום microelectromechanical, וכיצד להשתמש בו ביעילות ( כלומר, כוונון של יכולת הכוונון והימנעות כשל וגם stiction). LDV מאפשר מדידות חיוני שאי אפשר. עם מנתח רשת, כגון זיהוי מצב גבוה יותר (יישום ביוסנסור רגישה מאוד) ומדידה תהודה להתקנים קטנים מאוד (שטנץ מהירה). בהתאם לכך, LDV שימש לאפיין את התדרים כוונון ותדר תהודה על מצבים שונים של המסננים MEMS שנבנה עבור מחקר זה. מנגנון כוונון של תדירות מגוון רחב זה מבוסס בפשטות על ג'ול חימום מחממי מוטבע, לחץ תרמית גבוהה יחסית הטמפרטורה של קרן קבועה-קבוע. עם זאת, נדגים כי הגבלה נוספת של שיטה זו הוא וכתוצאה מכך גבוהה תרמי הלחץ, והדבר עלול לצרוב את המכשירים. שיפור נוסף היה מושגת, מופיעה לראשונה במחקר זה, כגון יכולת כוונון הוגדל ב-32% דרך עלייה DC הסטייה מתח המופעל (25 V ל-35 V) בין שתי הקורות סמוכים. ממצא חשוב זה מבטל את הצורך ג'ול תוספת חימום-טווח הכוונון תדר רחב יותר. תקלה אפשרית אחרת היא דרך stiction ודרישת אופטימיזציה מבנה: אנו מציעים טכניקה פשוטה וקלה של יישום אות גל מרובע בתדר נמוך בהצלחה יכול להפריד בין הקורות, מבטלת את הצורך יותר שיטות מתוחכם ומורכב בהתחשב בספרות. הממצאים לעיל מחייבים מתודולוגיה לעיצוב, אז אנו מספקים עיצוב מבוסס-יישום.

Stiction היה נמנע על ידי החלת אות גל מרובע בתדר נמוך, זה אומתה באמצעות LDV (איור 1). כשל אפשרי עקב עומס תרמי גבוה14 בשעת החלת מתח DC הסטייה גבוהים יחסית על חימום מוטבע אומתה במיקרוסקופ (איור 2). התוכנית פמ שימש כדי להפיק את מצבי גבוה יותר ?...

Watch this Scientific Journal Video about Design and Characterization Methodology for Efficient Wide Range Tunable MEMS Filters at JoVE.com

Design and Characterization Methodology for Efficient Wide Range Tunable MEMS Filters

עיצוב, אפיון מתודולוגיה למסננים Tunable MEMS יעיל לטווח רחב

פרוטוקול עבור עיצוב קרן קבועה-קבוע באמצעות של לייזר דופלר ממדי רטט (LDV), כולל את המדידה של תדירות כוונון, שינוי של כוונון יכולת, והימנעות של כשל בהתקן, stiction, מוצג. העליונות של השיטה LDV מעל במנתח רשת הוא הפגין בשל היכולת למצב גבוה יותר.

Here, we demonstrate the advantages of the laser Doppler vibrometer (LDV) over conventional techniques (the network analyzer), as well as the techniques ...

design-characterization-methodology-for-efficient-wide-range-tunable

Research

JoVE Journal

Engineering

6.1K Views.  Harran University. פרוטוקול עבור עיצוב קרן קבועה-קבוע באמצעות של לייזר דופלר ממדי רטט (LDV), כולל את המדידה של תדירות כוונון, שינוי של כוונון יכולת, והימנעות של כשל בהתקן, stiction, מוצג. העליונות של השיטה LDV מעל במנתח רשת הוא הפגין בשל היכולת למצב גבוה יותר.

Video: Design and Characterization Methodology for Efficient Wide Range Tunable MEMS Filters

Fabrication of Silica Ultra High Quality Factor Microresonators

Whispering gallery resonant cavities confine light in circular orbits at their periphery.1-2 The photon storage lifetime in the cavity, quantified by the quality factor (Q) of the cavity, can be in excess of 500ns for cavities with Q factors above 100 million. As a result of their low material losses, silica microcavities have demonstrated some of the longest photon lifetimes to date1-2. Since a portion of the circulating light extends outside the resonator, these devices can also be used to probe the surroundings. This interaction has enabled numerous experiments in biology, such as single molecule biodetection and antibody-antigen kinetics, as well as discoveries in other fields, such as development of ultra-low-threshold microlasers, characterization of thin films, and cavity quantum electrodynamics studies.3-7
The two primary silica resonant cavity geometries are the microsphere and the microtoroid. Both devices rely on a carbon dioxide laser reflow step to achieve their ultra-high-Q factors (Q&gt;100 million).1-2,8-9 However, there are several notable differences between the two structures. Silica microspheres are free-standing, supported by a single optical fiber, whereas silica microtoroids can be fabricated on a silicon wafer in large arrays using a combination of lithography and etching steps. These differences influence which device is optimal for a given experiment.
Here, we present detailed fabrication protocols for both types of resonant cavities. While the fabrication of microsphere resonant cavities is fairly straightforward, the fabrication of microtoroid resonant cavities requires additional specialized equipment and facilities (cleanroom). Therefore, this additional requirement may also influence which device is selected for a given experiment.
Introduction
An optical resonator efficiently confines light at specific wavelengths, known as the resonant wavelengths of the device. 1-2 The common figure of merit for these optical resonators is the quality factor or Q. This term describes the photon lifetime (&tau;o) within the resonator, which is directly related to the resonator's optical losses. Therefore, an optical resonator with a high Q factor has low optical losses, long photon lifetimes, and very low photon decay rates (1/&tau;o). As a result of the long photon lifetimes, it is possible to build-up extremely large circulating optical field intensities in these devices. This very unique property has allowed these devices to be used as laser sources and integrated biosensors.10
A unique sub-class of resonators is the whispering gallery mode optical microcavity. In these devices, the light is confined in circular orbits at the periphery. Therefore, the field is not completely confined within the device, but evanesces into the environment. Whispering gallery mode optical cavities have demonstrated some of the highest quality factors of any optical resonant cavity to date.9,11 Therefore, these devices are used throughout science and engineering, including in fundamental physics studies and in telecommunications as well as in biodetection experiments. 3-7,12
Optical microcavities can be fabricated from a wide range of materials and in a wide variety of geometries. A few examples include silica and silicon microtoroids, silicon, silicon nitride, and silica microdisks, micropillars, and silica and polymer microrings.13-17 The range in quality factor (Q) varies as dramatically as the geometry. Although both geometry and high Q are important considerations in any field, in many applications, there is far greater leverage in boosting device performance through Q enhancement. Among the numerous options detailed previously, the silica microsphere and the silica microtoroid resonator have achieved some of the highest Q factors to date.1,9 Additionally, as a result of the extremely low optical loss of silica from the visible through the near-IR, both microspheres and microtoroids are able to maintain their Q factors over a wide range of testing wavelengths.18 Finally, because silica is inherently biocompatible, it is routinely used in biodetection experiments.
In addition to high material absorption, there are several other potential loss mechanisms, including surface roughness, radiation loss, and contamination loss.2 Through an optimization of the device size, it is possible to eliminate radiation losses, which arise from poor optical field confinement within the device. Similarly, by storing a device in an appropriately clean environment, contamination of the surface can be minimized. Therefore, in addition to material loss, surface scattering is the primary loss mechanism of concern.2,8
In silica devices, surface scattering is minimized by using a laser reflow technique, which melts the silica through surface tension induced reflow. While spherical optical resonators have been studied for many years, it is only with recent advances in fabrication technologies that researchers been able to fabricate high quality silica optical toroidal microresonators (Q&gt;100 million) on a silicon substrate, thus paving the way for integration with microfluidics.1
The present series of protocols details how to fabricate both silica microsphere and microtoroid resonant cavities. While silica microsphere resonant cavities are well-established, microtoroid resonant cavities were only recently invented.1 As many of the fundamental methods used to fabricate the microsphere are also used in the more complex microtoroid fabrication procedure, by including both in a single protocol it will enable researchers to more easily trouble-shoot their experiments.

We describe the use of a carbon dioxide laser reflow technique to fabricate silica resonant cavities, including free-standing microspheres and on-chip microtoroids. The reflow method removes surface imperfections, allowing long photon lifetimes within both devices. The resulting devices have ultra high quality factors, enabling applications ranging from telecommunications to biodetection.

ייצור של אולטרה סיליקה Microresonators באיכות גבוהה פקטור

Whispering gallery resonant cavities confine light in circular orbits at their periphery.1-2 The photon storage lifetime in the cavity, quantified by the ...

Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor

Refractive index (RI) sensing is a powerful noninvasive and label-free sensing technique for the identification, detection and monitoring of microfluidic samples with a wide range of possible sensor designs such as interferometers and resonators 1,2. Most of the existing RI sensing applications focus on biological materials in aqueous solutions in visible and IR frequencies, such as DNA hybridization and genome sequencing. At terahertz frequencies, applications include quality control, monitoring of industrial processes and sensing and detection applications involving nonpolar materials.
Several potential designs for refractive index sensors in the terahertz regime exist, including photonic crystal waveguides 3, asymmetric split-ring resonators 4, and photonic band gap structures integrated into parallel-plate waveguides 5. Many of these designs are based on optical resonators such as rings or cavities. The resonant frequencies of these structures are dependent on the refractive index of the material in or around the resonator. By monitoring the shifts in resonant frequency the refractive index of a sample can be accurately measured and this in turn can be used to identify a material, monitor contamination or dilution, etc.
The sensor design we use here is based on a simple parallel-plate waveguide 6,7. A rectangular groove machined into one face acts as a resonant cavity (Figures 1 and 2). When terahertz radiation is coupled into the waveguide and propagates in the lowest-order transverse-electric (TE1) mode, the result is a single strong resonant feature with a tunable resonant frequency that is dependent on the geometry of the groove 6,8. This groove can be filled with nonpolar liquid microfluidic samples which cause a shift in the observed resonant frequency that depends on the amount of liquid in the groove and its refractive index 9.
Our technique has an advantage over other terahertz techniques in its simplicity, both in fabrication and implementation, since the procedure can be accomplished with standard laboratory equipment without the need for a clean room or any special fabrication or experimental techniques. It can also be easily expanded to multichannel operation by the incorporation of multiple grooves 10. In this video we will describe our complete experimental procedure, from the design of the sensor to the data analysis and determination of the sample refractive index.

The procedure for implementing a refractive index sensor for terahertz frequencies based on a grooved parallel-plate waveguide geometry is described here. The method yields a measurement of the refractive index of a small volume of liquid through monitoring of the shift in the resonant frequency of the waveguide structure

חישת Terahertz Microfluidic באמצעות חיישן מוליך גל מקביל צלחת

Refractive index (RI) sensing is a powerful noninvasive and label-free sensing technique for the identification, detection and monitoring of microfluidic ...

Simulation, Fabrication and Characterization of THz Metamaterial Absorbers

Metamaterials (MM), artificial materials engineered to have properties that may not be found in nature, have been widely explored since the first theoretical1 and experimental demonstration2 of their unique properties. MMs can provide a highly controllable electromagnetic response, and to date have been demonstrated in every technologically relevant spectral range including the optical3, near IR4, mid IR5 , THz6 , mm-wave7 , microwave8 and radio9 bands. Applications include perfect lenses10, sensors11, telecommunications12, invisibility cloaks13 and filters14,15. We have recently developed single band16, dual band17 and broadband18 THz metamaterial absorber devices capable of greater than 80% absorption at the resonance peak. The concept of a MM absorber is especially important at THz frequencies where it is difficult to find strong frequency selective THz absorbers19. In our MM absorber the THz radiation is absorbed in a thickness of ~ &lambda;/20, overcoming the thickness limitation of traditional quarter wavelength absorbers. MM absorbers naturally lend themselves to THz detection applications, such as thermal sensors, and if integrated with suitable THz sources (e.g. QCLs), could lead to compact, highly sensitive, low cost, real time THz imaging systems.

This protocol outlines the simulation, fabrication and characterization of THz metamaterial absorbers. Such absorbers, when coupled with an appropriate sensor, have applications in THz imaging and spectroscopy.

סימולציה, ייצור ואפיון של בולמי metamaterial THz

Metamaterials (MM),  artificial materials engineered to have properties that may not be found in  nature, have been widely explored since the first ...

Implementation of a Reference Interferometer for Nanodetection

A thermally and mechanically stabilized fiber interferometer suited for examining ultra-high quality factor microcavities is fashioned. After assessing its free spectral range (FSR), the module is put in parallel with a fiber taper-microcavity system and then calibrated through isolating and eliminating random shifts in the laser frequency (i.e. laser jitter noise). To realize the taper-microcavity junction and to maximize the optical power that is transferred to the resonator, a single-mode optical fiber waveguide is pulled. Solutions containing polystyrene nanobeads are then prepared and flown to the microcavity in order to demonstrate the system&#8217;s ability to sense binding to the surface of the microcavity. Data is post-processed via adaptive curve fitting, which allows for high-resolution measurements of the quality factor as well as the plotting of time-dependent parameters, such as resonant wavelength and split frequency shifts. By carefully inspecting steps in the time-domain response and shifting in the frequency-domain response, this instrument can quantify discrete binding events.

A reference interferometer technique, which is designed to remove undesirable laser jitter noise for nanodetection, is utilized for probing an ultra-high quality factor microcavity. Instructions for assembly, setup, and data acquisition are provided, alongside the measurement process for specifying the cavity quality factor.

יישום של אינטרפרומטר הפניה לNanodetection

A thermally and mechanically stabilized fiber interferometer suited for examining ultra-high quality factor microcavities is fashioned. After assessing ...

Real-Time DC-dynamic Biasing Method for Switching Time Improvement in Severely Underdamped Fringing-field Electrostatic MEMS Actuators

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input bias voltage. However, the tradeoff for the improved switching performance is a relatively long settling time to reach each gap height in response to various applied voltages. Transient applied bias waveforms are employed to facilitate reduced switching times for electrostatic fringing-field MEMS actuators with high mechanical quality factors. Removing the underlying substrate of the fringing-field actuator creates the low mechanical damping environment necessary to effectively test the concept. The removal of the underlying substrate also a has substantial improvement on the reliability performance of the device in regards to failure due to stiction. Although DC-dynamic biasing is useful in improving settling time, the required slew rates for typical MEMS devices may place aggressive requirements on the charge pumps for fully-integrated on-chip designs. Additionally, there may be challenges integrating the substrate removal step into the back-end-of-line commercial CMOS processing steps. Experimental validation of fabricated actuators demonstrates an improvement of 50x in switching time when compared to conventional step biasing results. Compared to theoretical calculations, the experimental results are in good agreement.

The robust device design of fringing-field electrostatic MEMS actuators results in inherently low squeeze-film damping conditions and long settling times when performing switching operations using conventional step biasing. Real-time switching time improvement with DC-dynamic waveforms reduces the settling time of fringing-field MEMS actuators when transitioning between up-to-down and down-to-up states.

Real-Time DC-דינמית הטיית שיטה להחלפת זמן שיפור בשולים בשדה קשות Underdamped תנעי MEMS אלקטרוסטטית

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input ...

Fabrication and Testing of Microfluidic Optomechanical Oscillators

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including microresonators. However, because of the increased acoustic radiative losses during direct liquid immersion of optomechanical devices, almost all published optomechanical experiments have been performed in solid phase. This paper discusses a recently introduced hollow microfluidic optomechanical resonator. Detailed methodology is provided to fabricate these ultra-high-Q microfluidic resonators, perform optomechanical testing, and measure radiation pressure-driven breathing mode and SBS-driven whispering gallery mode parametric vibrations. By confining liquids inside the capillary resonator, high mechanical- and optical- quality factors are simultaneously maintained.

Parametric optomechanical excitations have recently been experimentally demonstrated in microfluidic optomechanical resonators by means of optical radiation pressure and stimulated Brillouin scattering. This paper describes the fabrication of these microfluidic resonators along with methodologies for generating and verifying optomechanical oscillations.

ייצור ובדיקה של מתנדים optomechanical Microfluidic

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including ...

Using Micro-Electro-Mechanical Systems (MEMS) to Develop Diagnostic Tools

Using Micro-Electro-Mechanical Systems MEMS to Develop Diagnostic Tools

I'm U De Mercy, I'm the principal investigator of Bio Stick MAMs in Medicine Labs. I did my PhD at Stanford University in electrical engineering. I did a postdoc at Harvard Medical School at MGH working on bio acoustic MAMs or mostly bio MAs.And now I'm continuing as a faculty at Harvard Medical School at Harvard MIT Health Sciences and Technology. And continuing with my research that I enjoy very much. The work that I did during my PhD was very much related to droplets and using acoustics to generate precise size droplets and control their location and position to deposit very sensitive polymers.Now we apply similar technologies to encapsulate cells in droplets and then position them on the surfaces for various applications in tissue engineering to print cells on the surfaces to pattern cells. Also, there are applications where you want to see that you can encapsulate few cells or a single cell or from the same population and to see the differences between the same population from one cell to another there being able to encapsulate cells in droplets at high throughput rates like 10, 000 cells per second kind of rates becomes very important and very useful to understand biological problems. So my research currently has two legs, I would say.One is this cell encapsulation work that I just talked about. How do we pack a cell in a droplet that's, and how can we do this repeatedly and reliably and without harming the cells? So after the cell is ejected or encapsulated in the droplet, we should be able to precisely located on a surface the cell should be functional and alive and viable.It shouldn't be harmed by the effects of ejection and so forth. So currently we have a system where we use acoustic drop focused waves to generate these droplets from open pools where we can encapsulate down to single cells in these really small droplets that are comparable to the cell size. That's very exciting in terms of applying this to cell printing and tissue engineering.The other side of my research is again using these MAMs micro electromechanical system technologies to develop low cost diagnostic tools. Mostly this research uses microfluidic approaches where we can introduce whole blood, very small volumes such as blood from a prick finger prick, less than 10 microliters that you can introduce to a chip. And from that blood we can encapsulate or you can capture certain sub-cellular populations from whole blood.Why is this important? Why should this be cheap for global health applications On top of the mountain in Africa, you want to be able to tell for a HIV patient, for instance, how many CD four T lymphocytes this patient has. Because World Health Organization says that below 200 CD four cells per microliter, you have to start treating the patients In the developed world, you use hundreds of thousands dollars of vert flow cytometers to be able to get this data.And it takes of course time to use and skill of course to be able to use these like huge table size machines. Our small chip can be introduced this small finger brick 10 microliters of whole blood and it'll capture the CD four cells using the surface protein affinities. And then you can rapidly count these cells that are captured because you know that there are CD four cells which are attached to CD four proteins antibodies on the surface of the chip.By controlling the flow rates and shear, you can make sure that the specificity and efficiency for these cell types are optimized. And there's of course always non specific binding, but by our sheer approaches we minimize these effects and make sure that between plus minus 10%errors, which is sufficient to make a diagnostic or prognostic decision on top mountain in Africa. So this has interesting applications for global health as well as these low cost techniques that are disposable can impact the developed world because now these fast blood tests which are really low cost can impact the tests that we use in the developed world.If they're optimized to higher levels of efficiency and specificity, which our initial data shows that they can be, then it'll definitely impact our lives. When I first finished my PhD, I knew more about microfluidics and that in MAMs more than anything else I could see, especially with the droplet application, I could see that if I could print cells and encapsulate cells or manipulate the few cells, single cells, that it'll have great applications in biotechnology area. And I was very interested in working on things that will actually impact people's lives.I used to apply these technologies to semiconductor industry, but then I wanted to to be useful directly to people. So I, that's what directed me towards problems in healthcare. And then that's why I made a big shift and came to a hospital, mass general hospital to the postdoc.And there, you know, I got exposed more and more to problems and it seems, and it's all clear that one of the biggest problems of the world today is global health and there comes illnesses like tuberculosis, HIV that kills thousands of people per day. And these people die not because the drugs are not there, but because there aren't enough diagnostic tools which is much more expensive than the existing drugs. So I know the technology side of the things very well.I get, I got exposed to the biological problems and the more I learned about them, the more I could see that I could make an impact. And that's how it all grew from there. And it's still continuing now.Like I seen biotechnology and in medicine there are like so many problems that actually directly cause our result into loss of people's lives and the technologies, the technology aspect of it and being able to apply it to real world medical problems is a great, I think path to follow. This is like how this whole biotechnology area I think is kind of growing and it's becoming very impactful. If you think about it, HIV cancer, those are big killers in the world.And current micro technologies, current approaches could maybe benefit from early detection of cancer by capturing these cells from blood or making it really cheap, which will make it available to masses. So all these things coming together, I think this whole microtechnology applications in healthcare in medicine could impact the future of human beings. So that's how all these things kind of come together I guess.And being in the Harvard MIT health sciences and technology where on one end you have the technology and on the other end you direct aspect, direct access to patients, direct access to doctors in Brigham and Women's Hospital where I work is a great environment. cause every person that you talk to have their problems and you could maybe it's coming from a different background, provide interesting solutions to those existing real world problems. So this is, I think how I see the whole perspective of how these medical problems meet the technology side.And we try to impact people's lives in a positive way. In single cell cap encapsulation or in cell encapsulation, the major challenge is to be able to encapsulate reliably and repeatably single cells. So you're ejecting 10, 000 hundred thousand cells per second.And how do you make sure that each droplet that you eject has a single cell? This statistics where you are changing the droplet size and minimizing the, optimizing the cell size over the droplet size, which goes into the old problem of packing spheres in a volume and what is the most efficient way to do it. So that's the biggest challenge in the cell printing area for from the technological side.The other aspect of it is now you can say print and precisely locate these cells. How can you generate these three dimensional tissues and how can you keep them alive and how can you transplant them? There comes in the biological end of the problems where you want to now exactly mimic the tissue.We have current approaches to be able to print an eyelet, a pancreas eyelet, and to be able to print using smooth muscle cells, a bladder tissue, directly mimicking what is in human or red bladder so that then we can make this tissue and test how well it performs compared to the real world existing native tissues. So that's the major challenge I guess by taking these novel technologies, how can you make this the ideal tissue that can be replaced, that can be transplanted, that's the, you know, biggest problem from the beginning because the control on single cell gives you the capability to precisely locate them. And then how do you kind of grow it from there?So it's something transplantable there where the impact of human life comes. So that's on that end, what the challenges are in the tissue engineering side of the things in southern encapsulation and in diagnostics using microfluidics, the challenge is to be able to capture a cell out of billions of cells. It's like you have a sugar particle in a salt can and you're trying to pull out that sugar particle and that's like one in a billion.So you, you're processing microliters to milliliters of whole blood and you want to be able to specifically and efficiently without any technological problems like clogging or any biological problems like non-specific binding, you want to be able to isolate at one cell out of billion cells in one microliter of whole blood, you have a few millions of cells. And for the CD four T lymphocyte case in that one microliter, we are after about thousand cells per microliter. So it's like one cell in a thousand kind of a problem where we have shown that it's doable.But when you want to go after circulating tumor cells for cancer, then the challenge becomes one in a billion. So to some summarize it, the challenge is how do we capture this one cell out of billions of other cells around it? And what is the technological aspects?What are the flow rates? What is the device design? What, what are the flow rates?What, what are the volumes of blood that has to be processed and how do you make sure that the cells you capture are the ones that you actually wanted to capture? All these aspects kind formed the whole challenge that can be summarized in one sentence, which is how do you capture this one rare cell out of billion others? So it's really a needle in a haystack kind of problem, which is exciting.And I think this is moving the technologies forward to address these problems is the current technological challenge. Being able to bring them to a level where they do the job that they're supposed to do is one thing. And then taking it to the clinic and making it a product has all different expertise such as being able to start a company, being able to patent these things and all those other aspects come into the picture.And I think we as scientists primarily don't have all of those skills that takes the products from desktop to products. So there comes in again, the importance of collaborations with people who have different backgrounds. And there are many technologies out there that I think could be very impactful and useful.They sometimes don't make it to the clinic or to the use of humankind either because it just didn't happen, wasn't the right time or other effects came into the picture that I just talked about. Or sometimes there isn't a direct link that you couldn't see that the technology could actually solve that problem. And the person who deals with the problem, or let's say the biologists or people in medicine are used to doing it one way for many years.And the people on the technology side mostly if you're not having a biotechnology focus, are not aware of the problems in medicine. So bringing these two sides together is a serious interdisciplinary research. And I think in the past years, the whole emphasis both at NIH level and that we see in research labs and universities is to generate interdisciplinary research.So people end up getting PhDs where they have to know multiple fields. For instance, for my PhD, I had to know acoustics, I had to know mems, I had to know microfluidics and I had to apply this for polymers. So now you see kinda very depth of knowledge in one field where you had to know actually three other fields quite well to be able to solve that problem.So I think the answer is in interdisciplinary research combined with people with business skills to make it available to use of the people, it's a whole big process and some inefficiencies that come in at certain locations. Cause that low percent of tech transfer.

שימוש Micro-Electro-Mechanical Systems (MEMS) לפתח כלים לאבחון

Biology

Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive. However, effective inspection and characterization metrology systems are needed to ensure the functional reliability of MEMS. This study presents a system based on digital holography as a tool for MEMS metrology. Digital holography has gained increasing attention in the past 20 years. With the fast development and decreasing cost of sensor arrays, resolution of such systems has increased broadening potential applications. Thus, it has attracted attention from both research and industry sides as a potential reliable tool for industrial metrology. Indeed, by recording the interference pattern between an object beam (which contains sample height information) and a reference beam on a CCD camera, one can retrieve the quantitative phase information of an object. However, most of digital holographic systems are bulky and thus not easy to implement on industry production lines. The novelty of the system presented is that it is lens-less and thus very compact. In this study, it is shown that the Compact Digital Holographic Microscope (CDHM) can be used to evaluate several characteristics typically consider as criteria in MEMS inspections. The surface profiles of MEMS in both static and dynamic conditions are presented. Comparison with AFM is investigated to validate the accuracy of the CDHM.

We present a compact reflection digital holographic system (CDHM) for inspection and characterization of MEMS devices. A lens-less design using a diverging input wave providing natural geometrical magnification is demonstrated. Both static and dynamic studies are presented.

עדשה-פחות קומפקטי מיקרוסקופ הולוגרפי הדיגיטלי פיקוח MEMS ואפיון

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and ...

Fabrication and Characterization of Superconducting Resonators

Superconducting microwave resonators are of interest for a wide range of applications, including for their use as microwave kinetic inductance detectors (MKIDs) for the detection of faint astrophysical signatures, as well as for quantum computing applications and materials characterization. In this paper, procedures are presented for the fabrication and characterization of thin-film superconducting microwave resonators. The fabrication methodology allows for the realization of superconducting transmission-line resonators with features on both sides of an atomically smooth single-crystal silicon dielectric. This work describes the procedure for the installation of resonator devices into a cryogenic microwave testbed and for cool-down below the superconducting transition temperature. The set-up of the cryogenic microwave testbed allows one to do careful measurements of the complex microwave transmission of these resonator devices, enabling the extraction of the properties of the superconducting lines and dielectric substrate (e.g., internal quality factors, loss and kinetic inductance fractions), which are important for device design and performance.

Superconducting microwave resonators are of interest for detection of light, quantum computing applications and materials characterization. This work presents a detailed procedure for fabrication and characterization of superconducting microwave resonator scattering parameters.

ייצור ואפיון של מהודי מוליכים

Superconducting microwave resonators are of interest for a wide range of applications, including for their use as microwave kinetic inductance detectors ...

Microparticle Manipulation by Standing Surface Acoustic Waves with Dual-frequency Excitations

We demonstrate a method for increasing the tuning ability of a standing surface acoustic wave (SSAW) for microparticles manipulation in a lab-on-a-chip (LOC) system. The simultaneous excitation of the fundamental frequency and its third harmonic, which is termed as dual-frequency excitation, to a pair of interdigital transducers (IDTs) could generate a new type of standing acoustic waves in a microfluidic channel. Varying the power and the phase in the dual-frequency excitation signals results in a reconfigurable field of the acoustic radiation force applied to the microparticles across the microchannel (e.g., the number and location of the pressure nodes and the microparticle concentrations at the corresponding pressure nodes). This article demonstrates that the motion time of the microparticle to only one pressure node can be reduced ~2-fold at the power ratio of the fundamental frequency greater than ~90%. In contrast, there are three pressure nodes in the microchannel if less than this threshold. Furthermore, adjusting the initial phase between the fundamental frequency and the third harmonic results in different motion rates of the three SSAW pressure nodes, as well as in the percentage of microparticles at each pressure node in the microchannel. There is a good agreement between the experimental observation and the numerical predictions. This novel excitation method can easily and non-invasively integrate into the LOC system, with a wide tenability and only a few changes to the experimental set-up.

A protocol for manipulating the microparticles in a microfluidic channel with a dual-frequency excitation is presented.

Microparticle מניפולציה על ידי עמידה גלי אקוסטית המשטח עם כפול בתדר Excitations

We demonstrate a method for increasing the tuning ability of a standing surface acoustic wave (SSAW) for microparticles manipulation in a lab-on-a-chip ...