Invention:
This invention is a proposed field modulation system that expands the upper wavelength limit of phase modulation achievable by a spatial light modulator. It combines a phase mask, spatial filter, and computational phase selection algorithm. This enables the creation of spatial light modulators that can modulate both phase and amplitude by trading in spatial resolution and modulator reflectance.
Background:
Typically, phase modulators such as Liquid Crystal on Silicon (LCoS) spatial light modulators and other phase light modulators have an upper wavelength limit in the visible or near infrared (NIR) bands, which inherently restricts the range of wavelengths they can modulate because their electro optic materials lose birefringence and exhibit increased absorption as wavelength increases, particularly beyond the NIR. Additionally, their reflective backplanes, thin film coatings, and pixel geometries are optimized for short wavelength operation, causing phase wrapping range, modulation depth, and efficiency to degrade as wavelengths extend toward the mid infrared and long wave infrared (LWIR) regions. Traditional modulator structures are too thin, too lossy, or insufficiently tunable for long wavelength operation. Combined, these material and structural constraints explain why conventional phase modulators are largely unavailable for LWIR applications, leaving a significant gap for technologies capable of phase control at longer wavelengths.
Applications:
- Material processing
- Medical imaging
- Laser surgery
- 3D printing of metallics
- Holographic displays
- LIDAR
- Spectroscopy
- Laser cutters and welders
- Additive manufacturing
Advantages:
- Inexpensive
- High-resolution
- High-speed
