An optical switch is disclosed which is electrically activatable through received photon energy. The switch may include a substrate responsive to photon energy that forms an optical excitation signal. First and second electrodes may be disposed on first and second surfaces of the substrate. The substrate may have a characteristic of two-photon absorption to enable electrical conduction through the substrate, the two-photon absorption being enhanced by deep energy levels located in a bandgap between conductance and valence bands of the substrate, which are at least near resonant with the photon energy.

Devices, apparatus, systems and methods for making and using laser pointers and laser illuminators with reduced risk of optical sensor damage such as eye injuries due to laser radiation from the pointer or illuminator, while scattered beams from the laser pointer or laser illuminator are visible to the optical sensor.

An aquarium photometer system includes a housing unit, an arm, and a mirror. The housing unit includes a light sensor configured to sense light incident on the light sensor and to convert the incident light to a signal. The housing unit also includes an operational amplifier including a first input node, a second input node, and an output node. The operational amplifier is configured to: receive the signal at the first input node, amplify a difference between the signal at the first input node and a signal at the second input node by a gain factor, and output the amplified signal on the output node. The housing unit also includes a potentiometer connected to the operational amplifier and configured to regulate the amplified signal; and a display connected to the potentiometer and configured to show an intensity of light detected by the light sensor based on the regulated amplified signal. The arm at a first end is connected to the housing unit and configured to move the housing unit around an aquarium case. The mirror is located on a bar and positioned within the aquarium in front of the light sensor and at a focal distance from the light sensor and configured to increase an amount of light incident on the light sensor.

A multi-channel photomultiplier tube (PMT) detector assembly includes a photocathode. The detector assembly includes a first dynode channel including a first set of dynode pathways. The first set of dynode pathways include a plurality of dynode stages configured to receive a first portion of the photoelectrons and direct a first amplified photoelectron current onto a first anode. The detector assembly includes an additional dynode channel including an additional set of dynode pathways. The additional set of dynode pathways includes a plurality of dynode stages configured to receive an additional portion of the photoelectrons and direct an additional amplified photoelectron current onto an additional anode. The detector assembly includes a grid configured to direct the first portion of the photoelectrons to one or more of the first set of pathways and an additional portion of the photoelectrons to one or more of the additional set of pathways.

A method for calibrating a test light to simulate a fire includes measuring a baseline resistance induced in a sensor cell of a two-color detector in response to a controlled fire. The method includes monitoring a test resistance induced in the sensor cell in response to exposure to emissions from a test light and adjusting the emissions of the test light until the test resistance of the sensor cell equals the baseline resistance of the sensor cell to achieve a calibration setting for the test light. A test light for a detector includes a housing and a first LED within the housing having a first emission wavelength. A second LED is within the housing. The second LED has a second emission wavelength. The second emission wavelength is different than the first emission wavelength.

To provide a solid-state imaging device with short image-capturing duration. A first photodiode in a pixel in an n-th row and an m-th column is connected to a second photodiode in a pixel in an (n+1)-th row and the m-th column through a transistor. The first photodiode and the second photodiode receive light concurrently, the potential in accordance with the amount of received light is held in a pixel in the n-th row and the m-th column, and the potential in accordance with the amount of received light is held in a pixel in the (n+1)-th row and the m-th column without performing a reset operation. Then, each potential is read out. Under a large amount of light, either the first photodiode or the second photodiode is used.

A laser scanning microscope for laser scanning a sample is provided. The laser scanning microscope includes a scanner that is operated at a predefined scanning speed and that is configured to change a direction of illumination light generated to illuminate the sample. A detector is configured to detect light that is returned from the sample and an amplifier assembly is connected to the detector and is configured to amplify a detection signal that is generated by the detector. The amplifier assembly includes an adjustable capacitor and a capacitance of the adjustable capacitor is adjusted depending on the scanning speed of the scanner.

A multichannel ASIC for interfacing with an array of photodetectors in a PET imaging system includes a front-end circuit configured to be coupled to the array of photodetectors and to receive analog signals therefrom. The ASIC includes a time discriminating circuit including a low input impedance amplifier configured to be coupled to the array of photodetectors and to receive a signal summing the analog signals from the array of photodetectors and to generate a hit signal for timing pickoff based on the signal. The ASIC includes an energy circuit operably coupled to the front-end circuit and configured to generate a summed energy output signal based on each of the analog signals and summed positional output signal based on each of the analog signals.

A multichannel ASIC for interfacing with an array of photodetectors in a PET imaging system includes a front-end circuit configured to be coupled to the array of photodetectors and to receive analog signals therefrom. The ASIC includes a time discriminating circuit including a low input impedance amplifier configured to be coupled to the array of photodetectors and to receive a signal summing the analog signals from the array of photodetectors and to generate a hit signal for timing pickoff based on the signal. The ASIC includes an energy circuit operably coupled to the front-end circuit and configured to generate a summed energy output signal based on each of the analog signals and summed positional output signal based on each of the analog signals.

A sensing device projects near-field spatial modulations onto a closely spaced photodetector array. Due to physical properties of the grating, the point-spread response distributes spatial modulations over a relatively large area on the array. The spatial modulations are captured by the array, and photographs and other image information can be extracted from the resultant data. An image-change detector incorporating such a sensing device uses very little power because only a small number of active pixels are required to cover a visual field.