There is no doubt that mechanical devices, such as mechanical laser beam steering systems and household cars, are always more vulnerable to damage over time. Especially for chemical sensing and LiDAR applications, mid-infrared beam scanning requires speed and reliability, while beam control mechanisms such as mechanical motion mirror and rotating prism often have slow speed and large energy consumption.
Us scientists have designed and developed a non-mechanical chip steering device for mid-infrared laser pointer beams, McCombs reports. Compared with similar technologies such as universal drive reflector, the chip can realize continuous two-dimensional scanning of 3 ~ 5um wavelength beams, and the scanning speed is faster.
The chip was developed by the U.S. naval research laboratory (U. S. Naval Research Laboratory, NRL) produces such a solid-state device as the Steerable electro-evanescent optical refractor (SEEOR). The chips have shown promise in turning light beams at telecommunications wavelengths and could one day be used in self-driving cars. NRL scientists believe their SEEOR is the first device that can operate at mid-infrared wavelengths.
The SEEOR looks like a small sandwich with multiple layers of film on the substrate and a trapezoidal piece of silicon on the side. The sandwich structure contains a thickness of about 1. 2um sulfo-glass passive waveguide core, liquid crystal layer and cover glass with patterned electrode. The entire chip is 48 long. 5mm, 14 wide. 5mm, depth 2. 75 mm.
From 4. The collimating light from a 6um wavelength quantum cascade laser enters the SEEOR at one end and the voltage applied to the electrode redirects the liquid crystal molecule, changing its refractive index in a controlled mode.
This proof-of-concept device can be used at 14°x 0. Steer the mid-infrared beam in a 6° 2-d range. Still, only about 3 percent of incident light can escape from the SEEOR’s other end, but NRL scientists say that by adding anti-reflective coatings and other optimizations to reduce internal scattering, the amount of light passing through can be greatly increased.