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Spectrally responsive optical filters
Color filters are widely used in instruments and devices such as liquid crystal display, imaging, detection, and spectrometric measurement. However, most color filters either are passive or have significant optical loss (at least 50%) from the passive polarizers. KOI has developed a remarkable reflective tunable notch color filter, which, featuring in a thin film configuration, reflects 100% of the light at a specific notch wavelength that can be tuned by varying the applied voltage. Outside the notch band, the filter passes close to 90% of the light. Tuning range as wide as 500 nm has been achieved in NIR region. [Back to top]
High Performance Holographic Liquid Crystal Devices
Made from a novel liquid crystal and polymer composite materials, the holographic liquid crystal device contains layered structure comprising alternatively spaced homogeneous liquid crystal and polymer layers. The new holographic liquid crystal device has high reflectivity ( ~ 99%), dramatically reduced haze, spectral tunability, and very long Bragg reflection wavelength (up to 3.3 micron in mid-wave Infrared).
In addition, the holographic liquid crystal device can be built into either reverse or normal operation mode, polarization sensitive or insensitive, single reflection peak or multi-reflection peaks. [Back to top]
Electrically Tunable Laser
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Made from a novel photonics band gap (PBG) material based on a special liquid crystal (LC), the tunable laser is free of external cavity, free of oscillator alignment and exhibits extra wide spectral tuning range (> 300 nm achievable; 55 nm has been demonstrated in our laboratory). This novel laser is expected to replace the existing alternatives (liquid dye lasers or frequency-doubled ＾optical parameter oscillation￣ (OPO)).
The video on the right illustrates a demo tunable laser under a frequency-doubled Q-switched Nd:YAG laser.
Click here to download the clip of the CLC Laser. [Back to top]
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Multi-functional Glazing
Multi-functional glazing with privacy protection, energy conservation and information display capability.
KOI has developed a remarkable large screen multi-functional glazing from liquid crystal for privacy protection, energy conservation and information display . The glazing has multiple functions of (a) opaque mode for privacy protection, (b) clear mode as a normal window, and (c) information (text) display mode. The glazing will be integrated into building interior as door and/or window panels with privacy protection and information display capability. [Back to top]
Electrically Switchable Reflector/Blocker
The switchable reflectors have been developed in both visible and near infrared region from a special liquid crystal technology. Under zero voltage, the liquid crystal reflector resembles a metallic mirror. It reflects >99% incident light within the band with high contrast ratio over 1,000:1. Under a sufficient voltage (Vmax), the mirror becomes optically transparent (like a clear glass) and near 90% of an unpolarized light is transmitted (the 10% light loss originates from the Fresnel reflection at the film surfaces and/or interfaces). Intermediate transmittance or reflectance can be achieved by adjusting the voltage between 0 and V max.[Back to top]
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