University of Central Florida Research Foundation Inc

Lam Mach

Ivan Divliansky

Leonid B Glebov

Zenghu Chang

Yanchun Yin

Xiaoming Ren

Leonid Glebov

An imaging element may include volume Bragg grating (VBG) within a material, where the material has an input face, and where the VBG is formed as a periodic distribution of curved surfaces of refractive index variation with chirped periodicity in a volume of the material. The periodic distribution of curved surfaces of refractive index variation forming the VBG may be selected to image different object planes oriented parallel to the input face onto different lateral locations of a single image plane with different wavelengths via the Bragg diffraction.

All-optical volumetric imaging via spectral sweep by means of a transmissive bragg grating featuring a radially dependent plane of diffraction

A phase-shifted longitudinally-chirped volume Bragg grating (PS-LCVBG) may be formed as a solid block of photosensitive material having a planar input face, where the photosensitive material includes a VBG formed as a periodic volumetric refractive index distribution characterized by a grating vector direction. A period of the VBG may longitudinally chirped to vary linearly along the grating vector direction. The VBG may further include a spatially-varying distribution of longitudinal phase shifts providing a spatially-varying distribution of reflectivity in a transverse plane normal to the grating vector direction, where light incident on the planar input face is at least partially reflected based on the spatially-varying distribution of reflectivity.

Phase-shifted, chirped volume Bragg gratings

The present invention demonstrates a technique for achieving milli-joule level and higher energy, broad bandwidth laser pulses centered around 2.4 micrometer with a kilohertz and other repetition rate. The key to such technique is to start with a broadband micro-joule level seed laser at around 2.4 micrometer, which could be generated through difference frequency generation, four-wave mixing process and other methods. This micro-joule level seed laser could then be amplified to above one milli-joule through chirped pulse amplification in a Cr2+:ZnSe or Cr2+:ZnS crystal pumped by a commercially available Ho:YAG or other appropriate suitable lasers. Due to the high seed energy, fewer gain passes are needed to achieve a milli-joule level output thus significantly simplifies laser architectures. Furthermore, gain narrowing effect in a typical chirped pulse amplifier is also mitigated and thus enable a broadband output.

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Orlando, FL, United States of America

Lam Mach