UC San Diego

High-speed imaging is invaluable in studying the dynamics of real-time ultrafast phenomena. However, conventional imaging techniques are ultimately limited by the electronic readout rate of the sensors. Compressive sensing (CS), a technique that allows for the reduction in the number of measurements needed to sample a signal, offers a method to bypass this limit. However, the lack of high-speed spatial light modulators provides a similar constraint on experimental realizations of CS cameras.

Etalons are optical structures that have unique and tunable transmission spectra. Ultrafast etalon array imaging uses an array of Fabry-Perot resonators to create a frequency dependent mask. This etalon array is combined with a method for high-speed frequency sweeping to generate high speed illumination patterns, which are used to sample an object. When combined with compressive sensing, it allows for a high-speed imaging capability. We demonstrate a proof of concept of this technology, showing high-speed tracking at a 12 ns exposure time and 25 kHz frame rate, and demonstrate an extension to high-speed particle tracking.

Also in this work, we demonstrate the capability for the etalon array to be used as a reconstructive spectrometer. The planar nature of the array allows for a spectrometer that is compact, robust, and potentially very inexpensive. We show a spectral resolution of 4 nm across a wide variety of visible wavelength bands, and explore extensions of the technology to hyperspectral imaging.