High speed self-pixelating low light level optical system

A device, comprising:

• an InGaAsP photodiode having a bandgap, the photodiode configured to operate in Geiger mode;
• a first light source configured to emit an optical signal of a first wavelength at a first intensity, the first wavelength less than the bandgap of the photodiode;
• a second light source configured to emit light of a second wavelength at a second intensity, the second wavelength greater than the bandgap of the photodiode;
• a beam combiner positioned within an optical path and configured to combine the first and second wavelengths to simultaneously irradiate the photodiode with the first and second wavelengths of light;
• an electric field applied across the photodiode greater than a breakdown voltage thereof, the electric field configured to result in avalanching of electrons in the photodiode when the optical signal from the first light source is incident thereon, the avalanche of electrons resulting in a photorefractive response within the photodiode;
• an image capture device in optical communication with and configured to capture modulated light of the second wavelength reflected from the photodiode;
• and
• a memory device coupled to the image capture device and configured to receive and store image information received therefrom.

A method comprising:

• biasing a photodiode to operate in Geiger mode;
• irradiating the photodiode with a first wavelength of light to which the photodiode is sensitive, the first wavelength of light transmitting an optical signal at a first intensity;
• irradiating the photodiode with a second wavelength of light to which the photodiode is insensitive, the second wavelength of light at a second intensity, the second intensity greater than the first intensity;
• modulating light reflected from a surface of the photodiode with a photorefractive reaction within the photodiode;
• capturing the modulated reflected light;
• and
• simultaneously irradiating the photodiode with the first and second wavelengths of light.

A method comprising

• configuring a photodiode to operate in Geiger mode;
• irradiating the photodiode with a first wavelength of light transmitting an optical signal at a first intensity;
• initiating a photorefractive reaction within the photodiode with a first wavelength of light;
• irradiating the photodiode with a second wavelength of light to which the photodiode is insensitive, the second wavelength of light at a second intensity, the photodiode being simultaneously irradiated with the first and second wavelengths of light;
• modulating light reflected from a surface of the photodiode with the photorefractive reaction within the photodiode;
• capturing the modulated reflected light;
• and
• processing the captured modulated light to form an image.