The primary proposed objective is to realize a broadband high-speed spatial light modulator (SLM) for microscopy applications. Current microscopy techniques frequently employ spatial light modulators to manipulate the phase and amplitude of light illuminating a sample or and/or transmitted by a sample. The phase and amplitude of light in the microscope illumination and/or imaging paths are engineered in application-specific ways to improve resolution, acquire quantitative data in addition to observational data, and increase the rate of information throughput. Current spatial light modulators are wavelength-dependent and relatively slow for certain applications, such as imaging neural activity. Therefore, microscopy methods employing this approach are restricted to collecting data at one wavelength and limited in the dynamic processes they can observe. To overcome these limitations, Boulder Nonlinear Systems proposes to capitalize in Phase II on the successful Phase I investigation of alternative phase modulation methods in a liquid-crystal spatial light modulator. The geometric phase modulation methods studied in Phase I are wavelength- independent, so modulation of the geometric phase by a SLM allows lateral (x-y) phase modulation of the wave front over an extended wavelength range. Implementation of this approach is currently limited by the low voltage of the backplanes on which the modulators are built. The proposed Phase II effort will develop a high- voltage backplane with which to implement a SLM based on geometric phase modulation. Moreover, the high- voltage backplane will result in a minimum 10x increase in spatial light modulator speed over current technology with a possible path to 100x speed improvement. The potential benefits of a high-speed broadband spatial light modulator to the field of microscopy include expanded capability and increased commercial accessibility of current microscopy methods using spatial light modulators as well as new avenues for innovative applied microscopy research.
Wave front engineering is a multi-disciplinary microscope system design approach, often implemented with an x-y variable light modulator, which is changing the fundamental limits of optical imaging. Realization of high speed (~1kHz) modulation across a broad range of wavelengths (within the visible range) may allow more efficient, higher precision observation of dynamic biological and chemical processes. Of particular interest is the potential application of the proposed technology to high-speed 3D imagery for mapping neural pathways in the brain.
