HOME > PRODUCTS > OPTICS & CRYSTALS > Waveplate & Filter
 
  Lens   SAM/SOC/SA   Others  Scan Lens, Mirror
  Crystals   Waveplate & Filter   Mirror & Window  Beamsplitter
  Prism   Microlens Array   Femtoline Optics  GRIN Lens
 
Waveplate
 
Low-Order Waveplates Zero-Order Waveplate True-Zero-Order Waveplate
Achromatic Waveplate Multi-Order Waveplates Fresnel Rhomb Prisms
Polarization Rotators Mounts and Holders  
 
Filter
Birefringent Filters Interference Filters Neutral Density Filters (Absorptive)
Neutral Density Filters
(Reflective)
Short Wave Pass Filters Long Wave Pass Filters
 
Principle of Waveplates
Waveplates are made from materials which exhibit birefringence. The velocities of the extraordinary and ordinary rays through the birefringent materials vary inversely with their refractive indices. The difference in velocities gives rise to a phase difference when the two beams recombine. In the case of an incident linearly polarized beam this is given by a= 2ð × d (ne-no)/e (a ?- phase difference; d - thickness of waveplate; ne, no - refractive indices of extraordinary and ordinary rays respectively; e-wavelength). At any specific wavelength the phase difference is governed by the thickness of the retarder.
 
Half Waveplate
The thickness of a half waveplate is such that the phase difference is 1/2 - wavelength (e/2, true-zero order) or some multiple of 1/2 - wavelength [(2n+1)e/2, multiple order].
A linearly polarized beam incident on a half waveplate emerges as a linearly polarized beam but rotates such that its angle to the optical axis is twice that of the incident beam. Therefore, half waveplates can be used as continuously adjustable polarization rotators. Half waveplates are used in rotating the plane of polarization, electro-optic modulation and as a variable ratio beamsplitter when used in conjunction with a polarization cube.
 
Quarter Waveplate
The thickness of the quarter waveplate is such that the phase difference is
1/4 wavelength (true-zero order) or some multiple of 1/4 wavelength [(2n+1)e/2,
multiple order].
A linearly polarized beam incident on a half waveplate emerges as a linearly polarized beam but rotates such that its angle to the optical axis is twice that of the incident beam. Therefore, half waveplates can be used as continuously adjustable polarization rotators. Half waveplates are used in rotating the plane of polarization, electro-optic modulation and as a variable ratio beamsplitter when used in conjunction with a polarization cube.
 
Filter
Absorption and particularly wavelength selective absorption is an important factor in the function of the filters. The two most commonly used absorbers are thin metallic films which are particularly insensitive to wavelength for absorption, and colored glasses which absorb wavelengths varied by as much as several orders of magnitudes in only tens of nanometers. Interference filters are multilayer dielectric thin film devices. Metallic films, colored glasses and thin dielectric films are used in our filters.