The present invention relates to a holographic storage device and method for simultaneously recording and reading on two sides, and pertains to the technical field of optical holographic storage. The device and method disclosed in the present invention use a characteristic that orthogonal light would not interfere with each other and a Bragg selectivity characteristic for holographic storage, and use two optical heads to constitute two interference fields orthogonal in polarization directions on two sides of a same position of a holographic storage medium, so as to perform two-path simultaneous recording and reading on a hologram. The device and method provided in the present invention implement two-path parallel recording and reading of holographic storage, and combine shift multiplexing and circumferential rotation multiplexing, thereby improving the speed of an information data recording and reading process while increasing a capacity of the holographic storage.

The present invention relates to a holographic storage device and method for simultaneously recording and reading on two sides, and pertains to the technical field of optical holographic storage. The device and method disclosed in the present invention use a characteristic that orthogonal light would not interfere with each other and a Bragg selectivity characteristic for holographic storage, and use two optical heads to constitute two interference fields orthogonal in polarization directions on two sides of a same position of a holographic storage medium, so as to perform two-path simultaneous recording and reading on a hologram. The device and method provided in the present invention implement two-path parallel recording and reading of holographic storage, and combine shift multiplexing and circumferential rotation multiplexing, thereby improving the speed of an information data recording and reading process while increasing a capacity of the holographic storage.

An optical encoder is provided. The encoder includes an optical disc mounted on a shaft, the optical disc containing pit and land markings; an optical pickup unit for an optical disc that receives light from the optical disc and supplies as an output an electrical signal representative of the received light, comprising: a reading head objective lens, and dynamic steering actuators that control the focus and tracking of the reading head objective lens; a processor that receives as an input the electrical signal from the optical pickup unit and reports motion of the substrate based on the received at least one electrical signal.

An optical encoder is provided. The encoder includes an optical disc mounted on a shaft, the optical disc containing pit and land markings; an optical pickup unit for an optical disc that receives light from the optical disc and supplies as an output an electrical signal representative of the received light, comprising: a reading head objective lens, and dynamic steering actuators that control the focus and tracking of the reading head objective lens; a processor that receives as an input the electrical signal from the optical pickup unit and reports motion of the substrate based on the received at least one electrical signal.

A system includes a polarization selective optical element configured to diffract a light reflected by an object into a plurality of signal lights. The system also includes at least one optical sensor configured to receive the signal lights and generate a plurality of tracking signals for tracking the object.

A system includes a polarization selective optical element configured to diffract a light reflected by an object into a plurality of signal lights. The system also includes at least one optical sensor configured to receive the signal lights and generate a plurality of tracking signals for tracking the object.

An improved optical encoder uses an optical pick-up unit that provides for degrees of freedom in the tracking and focus axes that are unavailable in conventional optical encoders thereby improving the encoders' performance. In an embodiment the encoder employs an optical disc marked with pits and lands which may be arranged in a spiral pattern. The optical disc is mounted on the shaft whose motion is to be monitored by the optical encoder. The encoder may be arranged to read the markings on the optical disc using the three-beam pickup method.

An improved optical encoder uses an optical pick-up unit that provides for degrees of freedom in the tracking and focus axes that are unavailable in conventional optical encoders thereby improving the encoders' performance. In an embodiment the encoder employs an optical disc marked with pits and lands which may be arranged in a spiral pattern. The optical disc is mounted on the shaft whose motion is to be monitored by the optical encoder. The encoder may be arranged to read the markings on the optical disc using the three-beam pickup method.

A device for detecting light includes a photoreceptor array that is sensitive to the visible light spectrum and has a first wavelength sensor, a second wavelength sensor, and a third wavelength sensor. The first wavelength sensor has a first peak sensitivity at a first wavelength. The second wavelength sensor has a second peak sensitivity at a second wavelength. The third wavelength sensor has a third peak sensitivity at a third wavelength. The first wavelength sensor has a first base sensitivity at least 30% of the first peak sensitivity at the second wavelength and third wavelength. The second wavelength sensor has a second base sensitivity at least 30% of the second peak sensitivity at the first wavelength and third wavelength. The third wavelength sensor has a third base sensitivity at least 30% of the third peak sensitivity at the first wavelength and second wavelength.

A device for detecting light includes a photoreceptor array that is sensitive to the visible light spectrum and has a first wavelength sensor, a second wavelength sensor, and a third wavelength sensor. The first wavelength sensor has a first peak sensitivity at a first wavelength. The second wavelength sensor has a second peak sensitivity at a second wavelength. The third wavelength sensor has a third peak sensitivity at a third wavelength. The first wavelength sensor has a first base sensitivity at least 30% of the first peak sensitivity at the second wavelength and third wavelength. The second wavelength sensor has a second base sensitivity at least 30% of the second peak sensitivity at the first wavelength and third wavelength. The third wavelength sensor has a third base sensitivity at least 30% of the third peak sensitivity at the first wavelength and second wavelength.