The application provides a interface light path structure with all polarization-maintaining function. A first polarization-maintaining-transferring device includes a first port, a second port, and a third port, wherein the first port receives a first polarized light output by the polarization beam-splitting device, the second port is connected to the first Faraday rotation mirror, and the third port is connected to a first port of the first polarization-maintaining coupler. A second polarization-maintaining-transferring device includes a first port, a second port, and a third port, wherein the first port receives a second polarized light output by the polarization beam-splitting device, the second port is connected to the second Faraday rotation mirror, and the third port is connected to a second port of the first polarization-maintaining coupler.

An apparatus includes polarization beamsplitters that each separate incoming and outgoing optical signals having different polarizations. The apparatus also includes directionally-dependent polarization rotation optical assemblies that each maintain a polarization of one of the incoming and outgoing optical signals and to rotate a polarization of another of the incoming and outgoing optical signals. The apparatus further includes a third polarization beamsplitter that combines the outgoing optical signals to produce transmit optical signals and separate receive optical signals to produce the incoming optical signals.

A particle detection system may include a laser optical source providing a beam of electromagnetic radiation, one or more beam shaping elements for receiving the beam of electromagnetic radiation, an optical isolator disposed in the path of the beam, between the laser source and the one or more beam shaping elements, a particle interrogation zone disposed in the path of the beam, wherein particles in the particle interrogation zone interact with the beam of electromagnetic radiation, and a first photodetector configured to detect light scattered and/or transmitted from the particle interrogation zone, a second photodetector configured to monitor power of the beam, and a controller configured to adjust the beam power based on a signal from the second photodetector, wherein the optical isolator is configured to filter optical feedback from the particle detection system out of an optical path leading to the second photodetector. The particle detection system may be configured to have a lower detection limit of 5 nm to 50 nm effective particle diameter. The laser optical source may have a laser power of 300 milliwatts to 100 watts.

A method for producing an optical element having a main body with a first side surface, which has a first optical coating, and at least one second side surface, which is not plane-parallel to the first side surface and has a second optical coating, is proposed. The method includes the steps of: determining the stress induced in the optical element by the first optical coating of the first side surface; determining a counter-stress, so that the resultant overall stress induced in the optical element is as small as possible; determining the second optical coating while taking into account the determined counter-stress and the optical parameters of the second optical coating; applying the first optical coating on the first side surface; and, applying the second optical coating on the at least one second side surface.

A method for producing an optical element having a main body with a first side surface, which has a first optical coating, and at least one second side surface, which is not plane-parallel to the first side surface and has a second optical coating, is proposed. The method includes the steps of: determining the stress induced in the optical element by the first optical coating of the first side surface; determining a counter-stress, so that the resultant overall stress induced in the optical element is as small as possible; determining the second optical coating while taking into account the determined counter-stress and the optical parameters of the second optical coating; applying the first optical coating on the first side surface; and, applying the second optical coating on the at least one second side surface.

The present disclosure relates to magnetization-free Faraday rotator systems, apparatuses, and related methods. One such system comprises a Faraday rotator device comprising a magneto-optical composite material having first and second magnetic component materials in a periodic or uniform pattern in an X-Y plane, wherein the first and second magnetic component materials are magnetized along a Z-axis in opposite directions and the Faraday rotator device produces nonzero magnetic Faraday rotation for the electromagnetic wave propagating in a Z-axis direction in the absence of an external bias magnetic field.

The present disclosure relates to magnetization-free Faraday rotator systems, apparatuses, and related methods. One such system comprises a Faraday rotator device comprising a magneto-optical composite material having first and second magnetic component materials in a periodic or uniform pattern in an X-Y plane, wherein the first and second magnetic component materials are magnetized along a Z-axis in opposite directions and the Faraday rotator device produces nonzero magnetic Faraday rotation for the electromagnetic wave propagating in a Z-axis direction in the absence of an external bias magnetic field.

A paramagnetic garnet-type transparent ceramic characterized by being a sintered body of a terbium-containing composite oxide represented by formula (1) in which the linear transmittance at a wavelength of 1,064 nm at an optical path length of 15 mm is 83% or higher.
(Tb.sub.1-x-ySc.sub.xCe.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12  (1)
(In the formula, 0<x<0.08, 0≤y≤0.01, 0.004<z<0.16.)

An optical assembly includes a first polarization-sensitive reflector, a second polarization-sensitive reflector, and a Faraday rotator. The first polarization-sensitive reflector is positioned to transmit light having a first polarization, and reflect light having a second polarization that is orthogonal to the first polarization. The second polarization-sensitive reflector is positioned to reflect light having a third polarization that is different from the first polarization and the second polarization, and transmit light having a fourth polarization that is orthogonal to the third polarization. The Faraday rotator is disposed between the first polarization-sensitive reflector and the second polarization-sensitive reflector so that the Faraday rotator converts: (i) the light having the first polarization into the light having the third polarization, (ii) the light having the third polarization into the light having the second polarization, and (iii) the light having the second polarization into the light having the fourth polarization.

An optical assembly includes a first polarization-sensitive reflector, a second polarization-sensitive reflector, and a Faraday rotator. The first polarization-sensitive reflector is positioned to transmit light having a first polarization, and reflect light having a second polarization that is orthogonal to the first polarization. The second polarization-sensitive reflector is positioned to reflect light having a third polarization that is different from the first polarization and the second polarization, and transmit light having a fourth polarization that is orthogonal to the third polarization. The Faraday rotator is disposed between the first polarization-sensitive reflector and the second polarization-sensitive reflector so that the Faraday rotator converts: (i) the light having the first polarization into the light having the third polarization, (ii) the light having the third polarization into the light having the second polarization, and (iii) the light having the second polarization into the light having the fourth polarization.