Spectral linewidth narrowing of broad-area blue diode bar in V-shape external Talbot cavity.

A 1-D linear array of 23 high-power broad-area laser diode (BALD) beams in the blue spectral region (447 nm) is combined employing a V-shape external Talbot cavity in Littrow configuration. A surface grating provides optical feedback via self-imaged diffractive coupling to the diode bar and induces all the emitters to lase at a common central wavelength. The external cavity reduces the spectral linewidth of the free-running laser diode bar from several nm to 20-50 pm (FWHM) with the power level of 11.8 W. The narrow spectrum of the external cavity stabilized laser can be tuned in the range of 3-4 nm by adjusting the tilt angle of the grating while the laser diode bar is operated in constant current mode at a temperature of 20°C.

Spectral linewidth narrowing of two broad-area blue laser diodes (445 nm) with a common external cavity.

Two watt-level broad-area laser diodes were simultaneously locked into a common external cavity made using a surface grating in a Littrow configuration. The spectral linewidth of the combined laser beam was narrowed down from over a nanometer to 10-15 pm (FWHM), and the output power was the sum of the power of the individually locked laser diodes. The spectrum of the combined laser beam can be tuned over a range of 2-3 nm by changing the tilt angle of the grating and varying the injection currents of each laser diode.

Broadband cholesteric liquid crystal lens for chromatic aberration correction in catadioptric virtual reality optics.

A planar and broadband cholesteric liquid crystal (CLC) lens is designed, fabricated, and hybridized with a refractive lens to form a catadioptric pancake lens for virtual reality (VR) displays. Due to their opposite optical dispersion behaviors, the chromatic aberration of the assembled pancake lens is dramatically suppressed, as verified by both ray-tracing analysis and experimental results. The demonstrated catadioptric pancake lens has great potential for next-generation VR displays.

On-chip surface plasmon resonance sensor.

A novel on-chip micro SPR (surface plasmon resonance) sensor based on an optoelectronic platform has been developed. This research aims for a fully integrated SPR sensor system to achieve a miniaturized, high throughput sensor system. A novel method for design and fabrication of the solid state SPR sensor device has been investigated. The generation and detection of the SPR sensor signal from the proposed platform has been proved using a simulated binding experiment.