femtosecond-laser-filaments-for-use-sub-diffraction-limited-imaging

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing

Probing remote matter with laser light is a ubiquitous technique used in circumstances as diverse as laser-induced breakdown spectroscopy and barcode ...

Texas A&M University

Baylor University

Optimization of laser output parameters vs. f-to-2f beating signals can be mutually contradicting, when an octave-spanning supercontinuum is employed for f-to-2f measurements. We show that resonant dispersive waves will solve this issue, thanks to their frequency stability against changes in laser power and chirping.

Power and chirp effects on the frequency stability of resonant dispersive waves generated in photonic crystal fibres.

We investigate the possibility of tailoring coherent Raman generated spectra via adaptive wavefront optimization. Our technique combines a spatial light modulator and a spectrometer providing a feedback loop. The algorithm is capable of controlling the Raman generation, producing broader spectra and an improved overall efficiency, and increasing the intensity of high-order sidebands. Moreover, by wavefront optimization we can extend the generated spectra towards the blue spectral region and increase the total power of generated sidebands. Mutual coherence and equal frequency separation of the multiple Raman sidebands are of interest for the synthesis of ultrashort light pulses with the total spectral bandwidth extending over ultraviolet, visible and near-infrared wavelengths.

Coherent Raman Generation Controlled by Wavefront Shaping.

Coherent Anti-Stokes Raman Spectroscopy (CARS) is performed on single spores (conidia) of the fungus Aspergillus nidulans in order to establish a baseline measurement for fungal spores. Chemical maps of single spores are generated and spectral differentiation between the cell wall and the cytoplasm is achieved. Principal Component Analysis of the measured spectra is then completed as a means to quantify spore heterogeneity. Applications range from the quick and accurate diagnosis of public health concerns to real-time agricultural and environmental sensing of fungal symbionts and pathogens.

Alexei V. Sokolov

Texas A&M University

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing