An optical unit includes: a first optical device holding body that is sleeve-shaped and includes a first holding portion configured to hold therein at least one first optical device, and a first fitting portion extending from the first holding portion; a second optical device holding body that is sleeve-shaped and includes a second holding portion configured to hold therein at least one second optical device, and a second fitting portion extending from the second holding portion; and a welded portion that is melted and solidified over the first fitting portion and the second fitting portion in an overlapping portion between the first fitting portion and the second fitting portion. A first welding width at a center of the first fitting portion and a second welding width at a center of the second fitting portion are substantially identical in the optical axis direction of the optical unit.

A method of performing a write operation in a holographic data storage system, in which schedule schedules at least one write operation across multiple non-contiguous write intervals, the write operation pertaining to a set of data to be stored in a region of a holographic recording medium. In each of the non-contiguous write intervals, the region of the holographic recording medium is exposed to an interference pattern caused by interference between a reference beam and an input beam carrying the set of data. The multiple non-contiguous write intervals have a total aggregate duration of sufficient length to cause a persistent state change in the exposed region, such that the set of data is recoverable from that region by the end of a final write interval of the multiple non-contiguous write intervals.

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 method of performing a write operation in a holographic data storage system, in which schedule schedules at least one write operation across multiple non-contiguous write intervals, the write operation pertaining to a set of data to be stored in a region of a holographic recording medium. In each of the non-contiguous write intervals, the region of the holographic recording medium is exposed to an interference pattern caused by interference between a reference beam and an input beam carrying the set of data. The multiple non-contiguous write intervals have a total aggregate duration of sufficient length to cause a persistent state change in the exposed region, such that the set of data is recoverable from that region by the end of a final write interval of the multiple non-contiguous write intervals.

Provided is a polarization state converting element including a plurality of waveplates, and a rotation mechanism that rotates the respective waveplates independently of one another around an optical axis. The waveplates are each configured by a substrate made of a material having no optical rotatory property but having birefringence, or are each made of a material having neither optical rotatory property nor birefringence, but having transparency, a function of phase delay depending on polarization being applied on a surface of each waveplate.

The purpose of the present invention is to control, with a simple structure and high accuracy, irradiation of excitation light to a multi-nanopore substrate without interrupting a measurement. Irradiation of excitation light is performed concurrently to at least one nanopore and at least one reference object on a substrate mounted in an observation container 103. A position irradiated with the excitation light in a measurement sample is calculated on the basis of a signal generated from the reference object detected by a detector 109, and the measurement and a fixed position control is performed concurrently by performing measurement of the measurement object while a drive control part 115 controlling the position of the irradiation of the excitation light to the measurement sample on the basis of the calculation result, whereby an analysis of the measurement sample can be performed in a short time.

The purpose of the present invention is to control, with a simple structure and high accuracy, irradiation of excitation light to a multi-nanopore substrate without interrupting a measurement. Irradiation of excitation light is performed concurrently to at least one nanopore and at least one reference object on a substrate mounted in an observation container 103. A position irradiated with the excitation light in a measurement sample is calculated on the basis of a signal generated from the reference object detected by a detector 109, and the measurement and a fixed position control is performed concurrently by performing measurement of the measurement object while a drive control part 115 controlling the position of the irradiation of the excitation light to the measurement sample on the basis of the calculation result, whereby an analysis of the measurement sample can be performed in a short time.

The optical information recording device includes a light source configured to emit a laser beam, an optical element configured to divide the laser beam into the reference beam and the signal beam, an angle control unit configured to control an angle of incidence of the reference beam on the optical information recording medium, and a phase control unit configured to control a phase of at least one of the signal beam and the reference beam in a recording period, wherein the angle control unit controls an angle interval so that a position of a 1st null of an adjacent page of the signal beam is fixed, and wherein the phase control unit controls the phase of the signal beam or the reference beam so that a phase difference between the adjacent pages is a predetermined value.

An optical disk drive with multiple optical pick-up heads is provided. The optical disk drive includes an upper cover, a base, a first carrier member, a second carrier member, a first limiting member, and a second limiting member. The base is disposed under the upper cover. The first carrier member disposed on the base and has a first optical pick-up head. The second carrier member is disposed on the upper cover and has a second optical pick-up head. The first limiting member is used for disposing the first end of the second carrier member on the upper cover. The second limiting member is used for disposing the second end of the second carrier member on the upper cover. The length of the first limiting member is larger than that of the second limiting member.

The optical information recording device includes a light source configured to emit a laser beam, an optical element configured to divide the laser beam into the reference beam and the signal beam, an angle control unit configured to control an angle of incidence of the reference beam on the optical information recording medium, and a phase control unit configured to control a phase of at least one of the signal beam and the reference beam in a recording period, wherein the angle control unit controls an angle interval so that a position of a 1st null of an adjacent page of the signal beam is fixed, and wherein the phase control unit controls the phase of the signal beam or the reference beam so that a phase difference between the adjacent pages is a predetermined value.