Plane polarized beam is not welcomed in some circumstances such as reflecting spectrometer. A depolarizer will change the plane polarization into a mix of polarization states by scrambling up the polarization, the result is to change plane polarized beam into pseudo-depolarized beam and produce depolarization. Depolarizer is widely used in polarization sensitive instrument.
Farview Optics' quartz Lyot depolarizer converts a polarized beam into a pseudo-random polarized beam. Regarding Linearly polarized beam from a monochromatic source, the output beam is converted to pseudo-depolarized beam with polarization state varies spatially. Linearly polarized beam comes from a broadband source which is transmitted through a quartz Lyot depolarizer will have a polarization that varies spatially as well as with wavelength. Farview Optics' quartz Lyot depolarizer consists of two crystal quartz wedges, the thickness of one is twice of the other. The optical axis of each wedge is in the plane of aperture, the orientation angle between two optical axes is 45°. The unique design of the quartz Lyot depolarizer does not require orienting the optical axes of a depolarizer at a specific angle, which is especially useful where the initial polarization state of the light is unknown or varies with time.
Regarding monochromatic light, we can only get good pseudo-random polarization when the input diameter is bigger than 6mm. The minimum beam diameter requirement comes from that randomization of the output beam's polarization is achieved by producing a spatial variation when the light hits on the wedge surface. Regarding a broadband source, it does not have the same beam diameter restriction because of the wavelength dependent retardation and also spatial variation.
No Requirement Of Optical Axis Alignment
Ideal for >6mm Diameter Monochromatic Light & Broadband Light
Epoxy Cemented or Optically Contacted Available
Dimension Tolerance +0/-0.2mm
Thickness Tolerance ±0.2mm
Surface Quality 60/40
Parallelism <1 arc minute
Beam Deviation <3 arc minutes
Clear Aperture >90% central
Damage Threshold Cemented: >500mJ/cm2, 20ns, 20Hz @1064nm
Optically contacted: >5J/cm2, 20ns, 20Hz @1064nm