Liquid Crystal Operating Principles
Meadowlark Optics DOWNLOAD PRINCIPLES Liquid Crystal Variable Retarders are solid
Liquid Crystal Variable Attenuator
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$1,716.00 – $4,202.00
Key Features
- High contrast ratio
- Computer control capabilities
- Continuous control of light intensity
Meadowlark Optics’ Liquid Crystal Variable Attenuator (LCVA) offers real-time, continuous control of light intensity. Our attenuator consists of an LC Variable Retarder (with attached compensator) operating between crossed linear polarizers. With crossed polarizers, light transmission is maximized by applying the correct voltage to achieve half-wave retardance from the LC cell. Half-wave operation rotates the incoming polarization direction by 90°, so that light is passed by the second polarizer. Minimum transmission is obtained with the retarder operating at zero (or a whole number of) waves.
Transmission decreases as the applied AC voltage amplitude increases (half- to zero-waves retardance). The relationship between transmittance T and retardance (in degrees) for crossed polarizer configuration is given by: T(Θ) = 1/2 [1 – cos(Θ)] Tmax, where Tmax is the maximum transmittance when retardance is exactly one-half wave (or 180°).Common Specifications
Retarder Material: Nematic liquid crystal with Birefringent polymer
Polarizer Material: Dichroic polymer
Substrate Material: Optical quality synthetic fused silica
Contrast Ratio: 500:1 at single wavelength
Transmitted Wavefront Distortion: (P – V at 632.8 nm) ≤ λ/4
Surface Quality: 40 – 20 scratch-dig
Beam Deviation: ≤ 2 arc min
Reflectance (per surface): ≤ 0.5% at normal incidence
Diameter Tolerance: ± 0.005 in.
Temperature Range: 0 ˚C to + 50 ˚C
Safe Operating Limit: 1 W/cm², CW (with dichroic polarizers)
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Item # | Size | Optimized Wavelength | Wavelength Range | Clear Aperture | Thickness | Lead Time | Price | Add to cart |
|---|---|---|---|---|---|---|---|---|
LVA-100-VIS | 1.000 in. (25.40 mm) | 632.8 | 405-700 | 0.370 in. (9.4 mm) | 1.415 in. (35.94 mm) | 2 weeks | $1,716.00 | |
LVA-100-IR1 | 1.000 in. (25.40 mm) | 785 | 650-950 | 0.370 in. (9.4 mm) | 1.415 in. (35.94 mm) | 2 weeks | $1,716.00 | |
LVA-100-IR2 | 1.000 in. (25.40 mm) | 1064 | 900-1250 | 0.370 in. (9.4 mm) | 1.415 in. (35.94 mm) | 2 weeks | $1,716.00 | |
LVA-100-IR3 | 1.000 in. (25.40 mm) | 1550 | 1200-1700 | 0.370 in. (9.4 mm) | 1.415 in. (35.94 mm) | 2 weeks | $1,716.00 | |
LVA-200-VIS | 2.000 in. (50.80 mm) | 632.8 | 405-700 | 0.700 in. (17.8 mm) | 1.125 in. (28.58 mm) | 2 weeks | $2,585.00 | |
LVA-200-IR1 | 2.000 in. (50.80 mm) | 785 | 650-950 | 0.700 in. (17.8 mm) | 1.125 in. (28.58 mm) | 2 weeks | $2,585.00 | |
LVA-200-IR2 | 2.000 in. (50.80 mm) | 1064 | 900-1250 | 0.700 in. (17.8 mm) | 1.125 in. (28.58 mm) | 2 weeks | $2,585.00 | |
LVA-200-IR3 | 2.000 in. (50.80 mm) | 1550 | 1200-1700 | 0.700 in. (17.8 mm) | 1.125 in. (28.58 mm) | 2 weeks | $2,585.00 | |
LVA-300-VIS | 3.000 in. (76.20 mm) | 632.8 | 405-700 | 1.710 in. (43.43 mm) | 3-4 weeks | $4,202.00 | ||
LVA-300-IR1 | 3.000 in. (76.20 mm) | 785 | 650-950 | 1.710 in. (43.43 mm) | 3-4 weeks | $4,202.00 |
Liquid Crystal Variable Attenuator
Maximum transmission is dependent upon properties of the LC Variable Retarder as well as the polarizers used in your system.
Extinction ratio is defined as the maximum transmission (LC cell at half-wave) divided by the minimum transmission (LC cell at zero waves). Values exceeding 1000:1 can be obtained for a single wavelength by optimizing the applied voltage levels for minimum and maximum transmission. We guarantee a minimum extinction ratio of 500:1 at your specified wavelength.
See Details
A Liquid Crystal Variable Attenuator can be configured with high efficiency calcite or beamsplitting polarizers to maximize light transmittance and increase damage threshold. With a linearly polarized input beam and a calcite polarizer, transmittance values exceed 90% at most wavelengths. Very high extinction ratios in excess of 5000:1 can be achieved with custom double attenuators. In this design, two Liquid Crystal Variable Retarders are combined with three polarizers.
SPECIFICATIONS | |
Retarder Material | Nematic liquid crystal with Birefringent polymer |
Polarizer Material | Dichroic polymer |
Substrate Material | Optical quality synthetic fused silica |
We offer standard liquid crystal variable attenuators to cover four spectral regions: VIS: 450 – 700 nm IR 1: 650 – 950 nm IR 2: 900 – 1250 nm IR 3: 1200 – 1700 nm | |
Contrast Ratio | 500:1 at single wavelength |
Transmitted Wavefront Distortion (P – V at 632.8 nm) | ≤ λ/4 (each component) |
Surface Quality | 40 – 20 scratch-dig |
Beam Deviation | ≤ 2 arc min |
Reflectance (per surface) | ≤ 0.5% at normal incidence |
Diameter Tolerance | ±0.005 in. |
Temperature Range | 0 ˚C to + 50 ˚C |
Safe Operating Limit | 1 W/cm², CW (with dichroic polarizers) |
Ordering Information – Contact Us or Buy Online
ORDERING INFORMATION | |||
Diameter in. (mm) | Clear Aperture | Thickness in. (mm) | Part Number |
1.00 (25.4 mm) | 0.37 (9.4 mm) | 1.23 (31.24 mm) | LVA – 100 – λ |
2.00 (50.8 mm) | 0.70 (17.8 mm) | 0.75 (19.05 mm) | LVA – 200 – λ |
3.00 (76.2 mm) | 1.60 (40.64 mm) | 1.00 (25.4 mm) | LVA – 300 – λ |
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