MWIR TPA Notch Filter

EPIR proposes to develop HgCdTe and InGaAs -based spectrally agile notch filters that are capable of autonomously attenuating pulses from an incoming mid-wavelength infrared (MWIR) laser threat while simultaneously transmitting scene energy critical to the normal operation of the imaging system. These filters use two-photon absorption (TPA) nonlinear response of narrow bandgap semiconductor materials to attenuate high laser photon flux. The filter response time is in picosecond range, and the recovery time is equally fast. The increase in size, weight and power consumption (SWaP) of the imaging system is minimal. The design of the TPA notch filter assembly not only significantly increases camera and imaging systemÆs hostile beam protection capability but also allows monitoring of the electrical impedance of the filter, so that additional protection to the imaging system (e.g. electromechanical or electrochromic shutters) can be triggered. EPIR plans to design and fabricate a TPA notch filter to block laser threats with no restriction on acceptance angles, no moving parts, and no polarization sensitivity. By the end of the Phase II base period, a technical readiness level (TRL) 4 is projected, and during the option period, we will integrate the assembly with NavyÆs in-service beam control devices and cameras to achieve TRL 6. ĀĀDetailed design along with experimental characterization results confirming the fulfillment of NavyÆs performance requirements will be delivered.