Name: experimental methods for spin- and angle-resolved photoemission spectroscopy combined with polarization-variable laser
Uploaded: 2018-06-28T13:00:00.000+00:00
Duration: 9 min
Description: Watch this Scientific Journal Video about Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser at JoVE.com

M. Nakayama, S. Toyohisa, A. Fukushima teşekkür ediyoruz ve Y. Ishida için deneysel kurulumu için destekler. JSP'ler Grantin yardımından için bilimsel araştırma (B) aracılığıyla Proje No 26287061 ve Proje No ile genç bilim adamları (B) için fon minnetle anıyoruz 15K 17675. Bu eser de (yenilikçi alan "topolojik malzeme bilimi," vermek No. 16 H 00979) Japonya MEXT ve JSP'ler KAKENHI (Grant No. 16 H 02209) tarafından desteklenmiştir

1. örnek Mount ve yükleme
<ol><li>Tek-kristal örnekleri bı2Se313 yaklaşık bir 1 × 1 × 0,5 mm boyutunda kesme örnek tutucusu örneğe yapıştırmak için3 ve kullanım gümüş tabanlı epoksi.</li>
	<li>İskoç teyibini örnek yüzeyinde yapıştırın. Not: İskoç teyibini atomik temiz bir yüzey elde etmek için ultrahigh vakum (UHV) odası örnekte ayırmak için kullanılır.</li>
	<li>İçine yük kilit Dergisi örnek örnek yükleyin ve yük kilidi basınç 1 × 10-5 PA daha düşük olana pompa başlatın</li>
</ol>2. örnek fizyon
<ol><li>UHV Vana UHV hazırlık odası arasındaki yük kilidi açın.</li>
	<li>Örnek dergi yük kilit odasına bağlı doğrusal/döner feedthrough kullanarak yük kaya Hazırlık odasına taşıyın.</li>
	<li>Hazırlık odasına bağlı transfer çubuk tarafından dergi örnekten örnek almak.</li>
	<li>Örnek Dergisi yük kilide koy ve UHV Vanayı kapat.</li>
	<li>Hazırlık odası baskısı 5 × 10-7 PA tamamlanana kadar bekleyin</li>
	<li>Hazırlık odasında sallantı stick kullanarak İskoç teyibini soyma ve örnek UHV koşul altında ayırmak.</li>
</ol>3. örnek Transfer için ölçüm konumu
<ol><li>Örnek UHV ölçüm odasına aktarmak ve ölçüm odası ile donatılmış tornavida tarafından ana gonio aşamasına örnek düzeltmek.</li>
	<li>Gonio aşamalı ölçüm konuma taşımak ve mikrometre sahne tam olarak örnek konum Spektrometre odak üzerine taşımak için kullanın.</li>
</ol>4. 7eV-lazer Kur
<ol><li>Nd:YVO4 lazer açın. Not: Lazer yüksek tekrarlama oranı 120 MHz ile 355 nm lazer ışık üretir.</li>
	<li>Lazer ışını çekim açın ve lazer KBBF kristal ve 177 ikinci harmonik dalgası üzerinden geçer emin olun nm (6.994 eV) oluşturulur.</li>
	<li>7 eV-lazer gücü 355 nm lazer ile değişken zayıflatıcı gücünü değiştirerek optimize.</li>
</ol>5. ARPES veri toplama
<ol><li>Analyzer denetim yazılımı masaüstü bilgisayarda açın. Not: "Bir elektron saptırıcı ile kontrol ScientaOmicron analyzer için genel bir program olan SES yazılım" kullanın.</li>
	<li>Kurulum sırası menüsünden aşağıda seçin (Şekil 2, adım i.2-1) bar.</li>
	<li>ARPES yapılandırma (Şekil 3, adım ı.3-1) ve ARPES eşleme listesinde (Şekil 3, adım ı.3-2) photoelectron yansıtıcı yüzey eşleştirmeyle Fermi gerçekleştirmek için seçin.</li>
	<li>(Şekil 3, adım ı.3-3) Düzenle ' yi tıklatın ve Fermi yüzey eşleme-12 ° adım boyu 0.5 ° (Şekil 3, adım ı.3-4) ile bir emisyon açının θy 12 ° arasında değişen yapılandırın. Not: Hemisferik analyzer bir elektron saptırıcı ile bize örnek rotasyonlar olmadan Fermi yüzey eşlemek sağlar.</li>
	<li>(Şekil 2, adım i.2-3) Çalıştır ' ı tıklatın.</li>
</ol>6. SARPES veri toplama
<ol><li>El ile makine Kurulum Çözümleyicisi giriş yarık ve diyafram boyutu (resim 1) de dahil olmak üzere SARPES ölçüm için değiştirin.</li>
	<li>Kurulum sırası menüsünden aşağıda seçin (Şekil 2, adım i.2-2) bar.</li>
	<li>(Şekil 4, adım ı.4'te-1) yapılandırma Spin ve Normal listesinde (Şekil 4, adım ı.4'te-2) seçip Tamam (Şekil 4, adım ı.4'te-3)'ı tıklatın.</li>
	<li>DA30 (Şekil 5adım i.5-1) menü çubuğu ve Denetim tetaseçin... (DA30 açı (çapx, θy) yapılandırması için ayar panelini açmak içinŞekil 5adım i.5-2).</li>
	<li>Emisyon açı (çapx, θy) seçin SARPES spectra (Şekil 5adım i.5-3) almak (-6 °, 0 °) =.</li>
	<li>Manyetik alan iki kutuplu kondansatör banka VLEED hedef belirli eksen boyunca olumlu yönde manyetize kontrol ederek uygulamak (α: x, yveya z). Not: sistemimiz içinde buyurmak-e sevketmek ile [Şekil 6 (bir)] Bu işlem yapılabilir.</li>
	<li>Yoğunluk spektrum (Şekil 2, adım i.2-3) almak için Çalıştır ' ı tıklatın.</li>
	<li>Manyetik alan VLEED hedef α boyunca negatif yönde manyetize ve tarama yoğunluğu spektrum almaya başlamak için geçerli.</li>
	<li>Spin-polarizasyon ve spin çözüldü spectra hesaplayın.</li>
</ol>7. ışık polarizasyon bağımlılık taraması
<ol><li>λ/2-waveplate tam 7 eV-lazer ışık kutuplaşma ayarlamak için adım motor tarafından kontrollü açısını değiştirmek. Not: bizim sistemi, komut istemi [Şekil 6 (b)] ile bu işlem yapılabilir.</li>
	<li>X, y ve z eksenleri için spin çözüldü spectra al.</li>
	<li>Spin çözüldü spectra 0 ° yarım waveplate açıdan adım boyu 3 ° ile 102 ° değişen ışık polarizasyon bir fonksiyonu olarak inceden inceye gözden geçirmek.</li>
</ol>

<ol>
	<li>Damascelli, A., Hussain, Z., Shen, Z. -. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angle-resolved+photoemission+studies+of+the+cuprate+superconductors.">Angle-resolved photoemission studies of the cuprate superconductors.</a> Rev. Mod. Phys. 75 (2), 473-541 (2003).</li><li>Qiao, S., Kimura, A., Harasawa, A., Sawada, M., Chung, J. -. G., Kakizaki, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+compact+electron+spin+polarimeter+with+a+high+efficiency.">A new compact electron spin polarimeter with a high efficiency.</a> Rev. Sci. Instrum. 68 (12), 4390-4395 (1997).</li><li>Dil, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin+and+angle+resolved+photoemission+on+non-magnetic+low-dimensional+systems.">Spin and angle resolved photoemission on non-magnetic low-dimensional systems.</a> J. Phys. Condens. Matter. 21 (40), 403001 (2009).</li><li>Hoesch, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin-polarized+Fermi+surface+mapping.">Spin-polarized Fermi surface mapping.</a> J. Electron Spectrosc. 124 (2), 263-279 (2002).</li><li>Souma, S., Takayama, S., Sugawara, K., Sato, T., Takahashi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrahigh-resolution+spin-resolved+photoemission+spectrometer+with+a+mini+Mott+detector.">Ultrahigh-resolution spin-resolved photoemission spectrometer with a mini Mott detector.</a> Rev. Sci. Instrum. 81 (9), 096101 (2010).</li><li>Okuda, T., Kimura, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin-+and+angle-resolved+photoemission+of+strongly+spin-orbit+coupled+systems.">Spin- and angle-resolved photoemission of strongly spin-orbit coupled systems.</a> J. Phys. Soc. Jpn. 82 (2), 021002 (2013).</li><li>Okuda, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+spin-polarized+photoemission+spectrometer+with+very+high+efficiency+and+energy+resolution.">A new spin-polarized photoemission spectrometer with very high efficiency and energy resolution.</a> Rev. Sci. Instrum. 79 (12), 123117 (2008).</li><li>Jozwiak, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-efficiency+spin-resolved+photoemission+spectrometer+combining+time-of-flight+spectroscopy+with+exchange-scattering+polarimetry.">A high-efficiency spin-resolved photoemission spectrometer combining time-of-flight spectroscopy with exchange-scattering polarimetry.</a> Rev. Sci. Instrum. 81 (5), 053904 (2010).</li><li>Okuda, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+spin+resolved+spectroscopy+observation+machine+at+Hiroshima+Synchrotron+Radiation+Center.">Efficient spin resolved spectroscopy observation machine at Hiroshima Synchrotron Radiation Center.</a> Rev. Sci. Instrum. 82 (10), 103302 (2011).</li><li>Yaji, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+three-dimensional+spin-+and+angle-resolved+photoelectron+spectrometer+using+vacuum+ultraviolet+laser+light.">High-resolution three-dimensional spin- and angle-resolved photoelectron spectrometer using vacuum ultraviolet laser light.</a> Rev. Sci. Instrum. 87 (5), 053111 (2016).</li><li>Shimojima, T., Okazaki, K., Shin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-temperature+and+high-energy-resolution+laser+photoemission+spectroscopy.">Low-temperature and high-energy-resolution laser photoemission spectroscopy.</a> J. Phys. Soc. Jpn. 84 (7), 072001 (2015).</li><li>Augustine, S., Mathai, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth,+morphology,+and+microindentation+analysis+of+Bi2Se3,+Bi1.8In0.2Se3,+and+Bi2Se2.8Te0.2+single+crystals.">Growth, morphology, and microindentation analysis of Bi2Se3, Bi1.8In0.2Se3, and Bi2Se2.8Te0.2 single crystals.</a> Mater. Res. Bull. 36 (13), 2251-2261 (2001).</li><li>Hasan, M. Z., Kane, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colloquium:+Topological+insulators.">Colloquium: Topological insulators.</a> Rev. Mod. Phys. 82 (4), 3045-3067 (2010).</li><li>Ando, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topological+insulator+materials.">Topological insulator materials.</a> J. Phys. Soc. Jpn. 82 (10), 102011 (2013).</li><li>Zhang, H., Liu, C. -. X., Qi, X. -. L., Dai, X., Fang, Z., Zhang, S. -. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topological+insulators+in+Bi2Se3,+Bi2Te3+and+Sb2Te3+with+a+single+Dirac+cone+on+the+surface.">Topological insulators in Bi2Se3, Bi2Te3 and Sb2Te3 with a single Dirac cone on the surface.</a> Nature Phys. 5 (6), 438-442 (2009).</li><li>Cao, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+the+orbital+wavefunction+of+the+surface+states+in+three-dimensional+topological+insulators.">Mapping the orbital wavefunction of the surface states in three-dimensional topological insulators.</a> Nature Phys. 9 (8), 499-504 (2013).</li><li>Zhang, H., Liu, C. -. X., Zhang, S. -. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin-orbital+texture+in+topological+insulators.">Spin-orbital texture in topological insulators.</a> Phys. Rev. Lett. 111 (6), 066801 (2013).</li><li>Kuroda, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coherent+control+over+three-dimensional+spin-polarization+for+the+spin-orbit+coupled+surface+state+of+Bi2Se3.">Coherent control over three-dimensional spin-polarization for the spin-orbit coupled surface state of Bi2Se3.</a> Phys. Rev. B. 94 (16), 165162 (2016).</li><li>Meier, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interference+of+spin+states+in+photoemission+from+Sb/Ag(111)+surface+alloys.">Interference of spin states in photoemission from Sb/Ag(111) surface alloys.</a> J Phys-Condens Mat. 23 (7), 072207 (2011).</li><li>Dil, J. H., Meier, F., Osterwalder, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rashba-type+spin+splitting+and+spin+interference+of+the+Cu(111)+surface+state+at+room+temperature.">Rashba-type spin splitting and spin interference of the Cu(111) surface state at room temperature.</a> J Electron Spectrosc. 201, 42-46 (2015).</li><li>Yaji, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin-dependent+quantum+interference+in+photoemission+process+from+spin-orbit+coupled+states.">Spin-dependent quantum interference in photoemission process from spin-orbit coupled states.</a> Nature Commun. 8, 14588 (2017).</li><li>Noguchi, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+mapping+of+spin+and+orbital+entangled+wave+functions+under+interband+spin-orbit+coupling+of+giant+Rashba+spin-split+surface+states.">Direct mapping of spin and orbital entangled wave functions under interband spin-orbit coupling of giant Rashba spin-split surface states.</a> Phys. Rev. B. 95 (6), 04111(R) (2017).</li></ol>

Yazarlar onlar rakip hiçbir mali çıkarları var bildirin.

ARPES ve SARPES teknikleri elektronik grup yapıları grubu eşleme ve spin-algılama1,2ile çalışmak için yaygın olarak kullanılmaktadır. Yukarıda gösterilen bu genel avantajları yanı sıra lazer-SARPES optik dipol uyarma yörünge seçim kuralına göre wavefunction ve kuantum spin girişim spin-orbital kaplin yürürlükte görüntülenmesi için yeni bir teknik olarak istihdam edilebilir . Şekil 9 ve 10</stron...

Photoemission açı çözüldü spektroskopisi (ARPES) tekniği quasiparticle grup yapıları sağlam Birleşik1' deki araştırmak için en güçlü bir araç haline geldi. En iyi şekilde çekici özelliği ARPES, enerji ve momentum uzayda elektronik Birleşik karakterize etmek Grup eşleştirme için yeteneği var. Spin çözüldü ARPES (burada spin-dedektörleri, e.gile donatılmış SARPES). Mott dedektörü2,3, daha fazla spin karakter gözlenen grup yapıları4gidermek bize sağlar. Mott dedektörü spin iki eksen (x ve z, veya y ve z) ile ölçebilirsiniz beri iki Mott dedektörleri daha fazla kombinasyonu bir üç boyut4,5 spin yönde elde etmek izin verir . Birkaç on yıl için ancak, SARPES deneyler onların düşük verimlilik (genellikle 1/spin entegre ARPES ölçüm için kıyasla 10000) zarar3,4,5,6 ,7enerji ve açısal çözünürlük sınırlı oldu,. Son zamanlarda, SARPES enerji çözünürlüğe üzerinde exchange saçılma, sözde çok düşük enerjili elektron-kırınım (VLEED) dedektörü7,8,9 dayalı bir yüksek verimli spin dedektörü ile artış ,10. Bu dedektörü ile veri toplama süresi kısaltılmış ve veri kalitesi önemli ölçüde geliştirilmiştir. Son zamanlarda, SARPES büyük ölçüde elektronik Birleşik spin polarize ve özellikle spin-yörünge kaplin etkisi yüzey bantları7spin doku kaynaklanan adrese başarılı oldu.
Burada, biz SARPES istihdam ölçümleri bir kutuplaşma değişkenli vakum ultraviyole ile lazer ışığı (lazer-SARPES) ve bu kombine teknik büyük avantajları göstermektedir. Spin-yörünge birleştiğinde yüzey Birleşik BI2Se3soruşturma, biz iki lazer-SARPES yeteneklerini mevcut. İlk olarak, doğrusal polarize lazerler dipol geçiş rejimi, p- ve syörünge seçim kuralı nedeniyle-polarize ışık seçerek heyecanlandırmak eigen-wavefunctions farklı yörünge simetri ile bir parçası. Yörünge bir seçici uyarma SARPES, yani, orbital-seçici SARPES böylece kullanılabilir. İkinci olarak, üç boyutlu (3D) spin-algılama SARPES spin kuantum eksen yönünü gösterir ve doğrudan ışık-polarizasyon bağımlılığı tam bilgileri görüntüler. Bu iletişim kuralı kısaca güçlü spin-yörünge kaplin etkilerini incelemek için bu state-of--art lazer-SARPES teknik gerçekleştirmek için bir metodoloji açıklayın.
Lazer-SARPES sistemimiz Institute for Solid State fizik, Tokyo Üniversitesi11yer alır. Bizim lazer-SAPRES makine şematik çizim Şekil 1' de gösterilen. Polarizasyon değişkenli 7-eV lazer ışık12 örnek yüzeyi aydınlatan ve photoelectrons örnek yayılan. Lazer kutuplaşma otomatik olarak MgF2- tabanlı λ/2 - ve seçmeli olarak doğrusal ve dairesel kutuplaşmalar kullanmak için λ/4-waveplates tarafından kontrol edilir. Hemisferik elektron analyzer photoelectrons düzeltir ve onların kinetik enerji (Ekin) ve emisyon açı (çapx ve θy) analiz eder. Photoelectron yoğunluklarda Ekin- CCD kamera tarafından izlenençapx ekran üzerinde eşleştirilir. Bu görüntü doğrudan enerji grup yapısı karşılıklı uzayda dönüşüyor.
SARPES ölçüm, belirli emisyon açı ve kinetik enerji elektron Çözümleyicisi tarafından analiz ile photoelectrons iki VLEED tipi spin yangın dedektörleri ile 90 derece photoelectron saptırıcı için yönlendirilir ve photoelectron kirişler iki odaklanmıştır farklı hedefler filmlerin oksijen tarafından sona Fe(001) -p(1 × 1). Hedefler tarafından yansıyan photoelectrons her spin Dedektör yerleştirilen bir channeltron kullanarak tek kanal algılama ile tespit edilir. VLEED hedefleri saygı ile dik geometri ile düzenlenmiş olan Helmholtz tipi elektrikli bobinleri ile mıknatıslı olmalı. Mıknatıslama yönü iki kutuplu kondansatör banka tarafından denetlenir. Çift Kişilik VLEED spin Dedektör böylece bize photoelectron üç boyutlu spin-polarizasyon vektör analiz etmek etkinleştirin.

<table><tbody><tr><td>DA30-L hemispherical analyzer</td><td>ScientaOmicron</td><td></td><td>http://www.scientaomicron.com/en/products/353/1170</td></tr><tr><td>Silver-based epoxy</td><td>Epoxy Technology</td><td>H20E</td><td></td></tr><tr><td>Sctoch tape</td><td>3M</td><td>801-1-18C</td><td></td></tr><tr><td>UHV valve</td><td>VAT</td><td>01034-KE01</td><td></td></tr><tr><td>linear/rotary feedthrough</td><td>Ferrovac</td><td>MD40</td><td></td></tr><tr><td>transfer rod</td><td>UHV design</td><td>PP series</td><td></td></tr><tr><td>wobble stick</td><td>Ferrovac</td><td>WM40</td><td></td></tr><tr><td>Paladin compact 355</td><td>Coherent</td><td></td><td></td></tr><tr><td>half waveplate</td><td>Kogakugiken</td><td></td><td>order made</td></tr><tr><td>Bipolar condenser bank</td><td>Tsuji electronics</td><td></td><td></td></tr></tbody></table>

experimental methods for spin- and angle-resolved photoemission spectroscopy combined with polarization-variable laser

Bu protokolü nasıl spin ve açı çözüldü photoemission spektroskopisi polarizasyon değişkenli 7-eV lazer (lazer-SARPES) ile birlikte gerçekleştirmek için mevcut ve katı hal fiziği çalışmak için bu teknik bir güç göstermek için hedeftir. Lazer-SARPES iki büyük yetenekleri sağlar. İlk olarak, yörünge seçim kuralı doğrusal polarize lazerlerin inceleyerek, yörünge seçici uyarma SAPRES deneyde yürütülen olabilir. İkinci olarak, teknik bir varyasyon spin kuantum eksen ışık polarizasyon bir fonksiyonu olarak tam bilgi gösterir. Lazer-SARPES bu yetenekleri işbirliği gücünü göstermek için spin-yörünge birleştiğinde yüzey Birleşik BI2Se3araştırmalar için bu tekniği uygulamak. Bu teknik spin ve yörünge spin-yörünge birleştiğinde wavefunctions bileşenlerinden çürümeye affords. Ayrıca, doğrudan spin algılama kullanarak bir temsilci avantajı polarizasyon-değişken laser ile işbirliği gibi teknik belirsizliğe yer bırakmadan spin kuantum eksen üç-boyut ışık polarizasyon bağımlılığının görüntüler. Lazer-SARPES önemli ölçüde photoemission teknik kapasitesini artırır.

SARPES deneyler başlamadan önce k pozisyonlar yüksek hayatinizda spin entegre ARPES sonuçları yüksek enerji - ve açısal-çözünürlük ile (5.1-5,5 iletişim kuralı) kullanarak spektrum spin çözüldü almak için doğru bir şekilde belirlenecektir gerekir. Bu nerede bir bı2Se3 tek kristal ARPES sonuçları sunulmuştur Şekil 7 ' de gösterilmiştir. Bu malzeme bir spin polarize yüzey Birleşik14...

Watch this Scientific Journal Video about Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser at JoVE.com

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

Burada, polarizasyon değişkenli 7-eV lazer spin-orbital kaplin etkisi katı Birleşik Devletleri görselleştirmek için spin ve açı çözüldü photoemission tekniği ile birleştirir.

Spin ve açı çözüldü Photoemission spektroskopisi polarizasyon değişkenli lazer ile kombine için deneysel yöntemleri

The goal of this protocol is to present how to perform spin- and angle-resolved photoemission spectroscopy combined with polarization-variable 7-eV laser ...

experimental-methods-for-spin-angle-resolved-photoemission

Research

JoVE Journal

Engineering

9.8K Görüntüleme.  University of Tokyo. Burada, polarizasyon değişkenli 7-eV lazer spin-orbital kaplin etkisi katı Birleşik Devletleri görselleştirmek için spin ve açı çözüldü photoemission tekniği ile birleştirir.

Video: Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

Ultra-düşük sıcaklıklarda Açı çözüldü Photoemission Spektroskopi

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

Mühendislik

Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

A protocol to detect and automate mode locking in a pre-adjusted nonlinear polarization rotation fiber laser is presented. The detection of a sudden change in the output polarization state when mode locking occurs is used to command the alignment of an intra-cavity polarization controller in order to find mode-locking conditions.

Çıktı Polarizasyon Ölçümler aracılığıyla Doğrusal Olmayan Polarizasyon Rotasyon Fiber Lazer Mod Kilitleme Otomasyonu

When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a ...

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

High resolution optical spectroscopy methods are demanding in terms of either technology, equipment, complexity, time or a combination of these. Here we demonstrate an optical spectroscopy method that is capable of resolving spectral features beyond that of the spin fine structure and homogeneous linewidth of single quantum dots (QDs) using a standard, easy-to-use spectrometer setup. This method incorporates both laser and photoluminescence spectroscopy, combining the advantage of laser line-width limited resolution with multi-channel photoluminescence detection. Such a scheme allows for considerable improvement of resolution over that of a common single-stage spectrometer. The method uses phonons to assist in the measurement of the photoluminescence of a single quantum dot after resonant excitation of its ground state transition. The phonon&#39;s energy difference allows one to separate and filter out the laser light exciting the quantum dot. An advantageous feature of this method is its straight forward integration into standard spectroscopy setups, which are accessible to most researchers.

The manuscript describes a method of phonon-assisted quasi-resonant fluorescence spectroscopy that incorporates both laser-limited resolution and photoluminescence (PL) spectroscopy. This method utilizes optical phonons to provide linewidth-limited resolution spectra of atom-like semiconductor structures in the energy domain. The method is also easily realized with a single spectrometer optical spectroscopy setup.

Yüksek Çözünürlüklü Fonon destekli Yarı-rezonans Floresans Spektroskopisi

High resolution optical spectroscopy methods are demanding in terms of either technology, equipment, complexity, time or a combination of these. Here we ...

Direct Imaging of Laser-driven Ultrafast Molecular Rotation

We present a method for visualizing laser-induced, ultrafast molecular rotational wave packet dynamics. We have developed a new 2-dimensional Coulomb explosion imaging setup in which a hitherto-impractical camera angle is realized. In our imaging technique, diatomic molecules are irradiated with a circularly polarized strong laser pulse. The ejected atomic ions are accelerated perpendicularly to the laser propagation. The ions lying in the laser polarization plane are selected through the use of a mechanical slit and imaged with a high-throughput, 2-dimensional detector installed parallel to the polarization plane. Because a circularly polarized (isotropic) Coulomb exploding pulse is used, the observed angular distribution of the ejected ions directly corresponds to the squared rotational wave function at the time of the pulse irradiation. To create a real-time movie of molecular rotation, the present imaging technique is combined with a femtosecond pump-probe optical setup in which the pump pulses create unidirectionally rotating molecular ensembles. Due to the high image throughput of our detection system, the pump-probe experimental condition can be easily optimized by monitoring a real-time snapshot. As a result, the quality of the observed movie is sufficiently high for visualizing the detailed wave nature of motion. We also note that the present technique can be implemented in existing standard ion imaging setups, offering a new camera angle or viewpoint for the molecular systems without the need for extensive modification.

We present a protocol for creating a real-time movie of a molecular rotational wave packet using a high-resolution Coulomb explosion imaging setup.

Lazer güdümlü Ultrafast Moleküler Rotasyon Doğrudan Görüntüleme

We present a method for visualizing laser-induced, ultrafast molecular rotational wave packet dynamics. We have developed a new 2-dimensional Coulomb ...

Kimya

Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising from metallic periodic arrays without involving time-resolved techniques. We have formulated the rates by quantities that can be measured by simple optical measurements. The instrumentation based on angle- and polarization-resolved reflectivity and photoluminescence spectroscopy will be described in detail here. Our approach is intriguing due to its simplicity, which requires routine optics and several mechanical stages, and thus is highly affordable to most of the research laboratories.

This protocol describes the instrumentation for determining the excitation and coupling rates between light emitters and Bloch-like surface plasmon polaritons arising from periodic arrays.

Uyarma ve oranları arasında ışık Emitters ve yüzey Plasmon Polaritons kaplin belirlenmesi

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising ...

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F&#8722;

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound electrons with neutral molecules/atoms. State-of-the-art in vacuo anion generation techniques allow application to a broad range of atomic, molecular, and cluster anion systems. These are separated and selected using time-of-flight mass spectrometry. Electrons are removed by linearly polarized photons (photo detachment) using table-top laser sources which provide ready access to excitation energies from the infra-red to the near ultraviolet. Detecting the photoelectrons with a velocity mapped imaging lens and position sensitive detector means that, in principle, every photoelectron reaches the detector and the detection efficiency is uniform for all kinetic energies. Photoelectron spectra extracted from the images via mathematical reconstruction using an inverse Abel transformation reveal details of the anion internal energy state distribution and the resultant neutral energy states. At low electron kinetic energy, typical resolution is sufficient to reveal energy level differences on the order of a few millielectron-volts, i.e., different vibrational levels for molecular species or spin-orbit splitting in atoms. Photoelectron angular distributions extracted from the inverse Abel transformation represent the signatures of the bound electron orbital, allowing more detailed probing of electronic structure. The spectra and angular distributions also encode details of the interactions between the outgoing electron and the residual neutral species subsequent to excitation. The technique is illustrated by the application to an atomic anion (F&#8722;), but it can also be applied to the measurement of molecular anion spectroscopy, the study of low lying anion resonances (as an alternative to scattering experiments) and femtosecond (fs) time resolved studies of the dynamic evolution of anions.

Here, we present a protocol for photoelectron imaging of anionic species. Anions generated in vacuo and separated by mass spectrometry are probed using velocity mapped photoelectron imaging, providing details of anion and neutral energy levels, anion and neutral structure and the nature of the anion electronic state.

F− 310 Nm dekolmanı tarafından resimli anyon photoelectron görüntüleme

Anion photoelectron imaging is a very efficient method for the study of energy states of bound negative ions, neutral species and interactions of unbound ...

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

We present a high-performance source of unconditional polarization-entangled photons that have a high-emission rate, a broadband distribution, are degenerated and postselection free. The property of the source is based on the multiple quantum interference effect with a round-trip configuration of a Sagnac interferometer. The quantum interference effects make it possible to use the high generation efficiency of the polarization-entangled photons to process parametric down-conversion, and separate degenerated photon pairs into different optical modes without a postselection requirement. The principle of the optical system was described and experimentally used to measure the fidelity and Bell parameters, and also to characterize the generated polarization-entangled photons from a minimum of six combinations of polarization correlated data. The experimentally obtained fidelity and Bell parameters exceeded the classical local correlation limit and are clear evidence of the generation of unconditional polarization-entangled photons.

We describe an optical system for the generation of unconditional polarization-entangled photons based on multiple quantum interference effects with a detection scheme to estimate the experimental fidelity of generated entangled photons.

Çoklu Kuantum Girişimine Dayalı Koşulsuz Polarizasyon-Dolaşık FotonLar Üretmek için Fotonik Sistem

We present a high-performance source of unconditional polarization-entangled photons that have a high-emission rate, a broadband distribution, are ...

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by local enhancement of electric field intensity that strengthens light-matter interactions, enabling applications such as surface-enhanced Raman scattering (SERS) and surface plasmon enhanced sensing. In the presence of magneto-optically active materials, the local field enhancement gives rise to anomalous magneto-optical activity. Typically, the confined modes of a given photonic crystal depend strongly on the wavelength and incidence angle of the incident electromagnetic radiation. Thus, spectral and angular-resolved measurements are needed to fully identify them as well as to establish their relationship with the magneto-optical activity of the crystal. In this article, we describe how to use a Fourier-plane (back focal plane) microscope to characterize magneto-optically active samples. As a model system, here we use a plasmonic grating built out of magneto-optically active Au/Co/Au multilayer. In the experiments, we apply a magnetic field on the grating in situ and measure its reciprocal space response, obtaining the magneto-optical response of the grating over a range of wavelengths and incident angles. This information enables us to build a complete map of the plasmonic band structure of the grating and the angle and wavelength dependent magneto-optical activity. These two images allow us to pinpoint the effect that the plasmon resonances have on the magneto-optical response of the grating. The relatively small magnitude of magneto-optical effects requires a careful treatment of the acquired optical signals. To this end, an image processing protocol for obtaining magneto-optical response from the acquired raw data is laid out.

Photonic band structure enables understanding how confined electromagnetic modes propagate within a photonic crystal. In photonic crystals that incorporate magnetic elements, such confined and resonant optical modes are accompanied by enhanced and modified magneto-optical activity. We describe a measurement procedure to extract the magneto-optical band structure by Fourier space microscopy.

Fotonik Nanoyapıların Spektral ve Açı Çözümlü Manyeto-Optik Karakterizasyonu

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by ...

In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence

Accurate control of the polarization states of laser light is important in precision measurement experiments. In experiments involving the use of a vacuum environment, the stress-induced birefringence effect of the vacuum windows will affect the polarization states of laser light inside the vacuum system, and it is very difficult to measure and optimize the polarization states of the laser light in situ. The purpose of this protocol is to demonstrate how to optimize the polarization states of the laser light based on the fluorescence of ions in the vacuum system, and how to calculate the birefringence of vacuum windows based on azimuthal angles of external wave plates with Mueller matrix. The fluorescence of 25Mg+ ions induced by laser light that is resonant with the transition of |32P3/2,F = 4, mF&#160;= 4<img align="center" alt="Equation 100" src="/files/ftp_upload/61175/61175img1.jpg" style="color: rgb(68, 0, 68); font-size: 18px; font-weight: 700;" />&#160;&#8594;&#160;|32S1/2,F = 3, mF&#160;= 3<img align="center" alt="Equation 100" src="/files/ftp_upload/61175/61175img1.jpg" style="color: rgb(68, 0, 68); font-size: 18px; font-weight: 700;" />&#160;is sensitive to the polarization state of the laser light, and maximum fluorescence will be observed with pure circularly polarized light. A combination of half-wave plate (HWP) and quarter-wave plate (QWP) can achieve arbitrary phase retardation and is used for compensating the birefringence of the vacuum window. In this experiment, the polarization state of the laser light is optimized based on the fluorescence of 25Mg+ ion with a pair of HWP and QWP outside the vacuum chamber. By adjusting the azimuthal angles of the HWP and QWP to obtain maximum ion fluorescence, one can obtain a pure circularly polarized light inside the vacuum chamber. With the information on the azimuthal angles of the external HWP and QWP, the birefringence of the vacuum window can be determined.

In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence

Presented here is a method to measure the birefringence of vacuum windows by maximizing the fluorescence counts emitted by Doppler cooled 25Mg+ ions in an ion trap. The birefringence of vacuum windows will change the polarization states of the laser, which can be compensated by changing the azimuthal angles of external wave plates.

25Mg+ Floresan Kullanılarak Vakum Pencere Birefringence Yerinde Ölçümü

Accurate control of the polarization states of laser light is important in precision measurement experiments. In experiments involving the use of a vacuum ...

Polarizasyona Duyarlı İki Foton Mikroskobu ile Sferülitlerin Karakterizasyonu

Polarization-Sensitive Two-Photon Microscopy for a Label-Free Amyloid Structural Characterization

Compared to its one-photon counterpart, two-photon excitation is beneficial for bioimaging experiments because of its lower phototoxicity, deeper tissue penetration, efficient operation in densely packed systems, and reduced angular photoselection of fluorophores. Thus, the introduction of polarization analysis in two-photon fluorescence microscopy (2PFM) provides a more precise determination of molecular organization in a sample compared to standard imaging methods based on linear optical processes. In this work, we focus on polarization-sensitive 2PFM (ps-2PFM) and its application in the determination of molecular ordering within complex bio-structures-amyloid spherulites. Neurodegenerative diseases such as Alzheimer's or Parkinson's are often diagnosed through the detection of amyloids-protein aggregates formed due to an impaired protein misfolding process. Exploring their structure leads to a better understanding of their creation pathway and consequently, to developing more sensitive diagnostic methods. This paper presents the ps-2PFM adapted for the determination of local fibril ordering inside the bovine insulin spherulites and spherical amyloidogenic protein aggregates. Moreover, we prove that the proposed technique can resolve the three-dimensional organization of fibrils inside the spherulite.

Yazar Spotlight: Polarizasyona Duyarlı İki Foton Mikroskobu Kullanarak Karmaşık Biyo-Yapıların İnvaziv Olmayan Görüntülenmesi 

This paper describes how polarization-sensitive two-photon microscopy could be applied to characterize the local organization within label-free amyloid superstructures-spherulites. It also describes how to prepare and measure the sample, assemble the required setup, and analyze the data to obtain information about the local organization of amyloid fibrils.

Etiketsiz amiloid yapısal karakterizasyonu için polarizasyona duyarlı iki foton mikroskobu

Compared to its one-photon counterpart, two-photon excitation is beneficial for bioimaging experiments because of its lower phototoxicity, deeper tissue ...

Spin ve açı çözüldü Photoemission spektroskopisi polarizasyon değişkenli lazer ile kombine için deneysel yöntemleri

Özet

Daha Fazla Video Keşfet

Bu videodaki bölümler