Electrooptic fabry-perot pixels for phase-dominant spatial light modulators
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorRichard A. Soref
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Abstract
Phase enhancement by resonant Fabry-Perot picture elements in III-V semiconductor spatial light modulators (SLMs) is disclosed. For 95% reflecting electrodes, a phase modulation of 0.7.pi. rad is found in transmission when the electrooptic input phase is 0.06.pi. rad. A resonant phase-dominant SLM in a 1.7-.mu.m-thick AlGaAs/GaAs multiple quantum well (MQW) structure can employ field effects and carrier-induced electrooptic effects within the MQWs.
Claims21
A resonant phase dominant Fabry Perot spatial light modulator for phase modulating light directed therethrough comprising:
- (a) a light transmissive array of p-i-n diodes having a semiconductor superlattice within intrinsic regions of said p-i-n diodes;
- (b) light transmissive partially reflecting first and second electrode means positioned upon opposite faces of said array of p-i-n diodes respectively, configured to form Fabry Perot resonators;
- (c) means for directing light to be phase modulated through at least one of said electrode means and a said array of p-i-n diodes;
- and
- (d) electric field producing means coupled to said electrode means, for producing a Wannier-Stark blue shift in the absorption spectrum of said superlattice, sufficient to induce electro-optic phase excursions in said p-i-n diodes within a critical rapid phase change region positioned about a Fabry Perot amplitude resonance point of said Fabry Perot resonators, for in turn producing large output phase changes in said light transmitted directed through said array of p-i-n diodes.
A resonant phase dominant spatial light modulator for phase modulating light directed therethrough comprising:
- (a) a light transmissive multiple quantum well (MQW) body including an array of p-i-n diodes having quantum well stacks within intrinsic regions of said p-i-n diodes;
- (b) light transmissive partially reflecting first and second electrode means positioned upon opposite faces of said array of p-i-n diodes respectively, configured to form Fabry-Perot resonators having a given Fabry-Perot amplitude resonance point;
- (c) biasing means for causing said p-i-n diodes to assume a first electrical state or a second electrical state, said biasing means including means for injecting carriers into said p-i-n diodes when said p-i-n diodes assume said second electrical state;
- and
- (d) means for directing light through said array of p-i-n diodes having a photon energy below the MQW band gap when said p-i-n diodes assume either said first state or said second state and said light having a wavelength which is off-resonance with respect to the Fabry-Perot amplitude resonance point when said p-i-n diodes assume said first electrical state or said second electrical state.
Dependencies are inferred from the claim text.