Liquid Crystal Devices

Achromatic Ferroelectric Liquid Crystal Devices

Sintec Optronics’ Ferroelectric Liquid Crystal (FLC) devices offer a significant performance advantage in optical shutter and rotator applications demanding the fastest optical response times available. FLC devices are designed for applications requiring active timing control of beam transmittance. Key features of our FLC devices include high-speed binary operation, high purity linear polarized output, and maximum extinction ratio performance. Since these devices are solid state – undesirable mechanical motion, associated noise, and vibration problems are eliminated. Our FLC devices require a DC-balanced AC drive signal, typically resulting in a 50% duty cycle operation. Our optional FC 5010 Controller is ideal for driving the devices for optimal performance (sold separately).

FLC Controller (FCS010)

The FCS010 is a two-channel liquid crystal controller specifically designed to drive our ferroelectric liquid crystal shutters and rotators. The FCS010 has two short-circuit protected output channels driven 180 degrees out of phase. The pre-configured controller waveforms are optimized for FLC devices. We can tailor the waveform to your specific needs based on application and purchased FLC device. The drive waveform is output through SMA connectors. The controller is 100% RoHS compliant and is powered by a separate 12V international power supply.

Features:

• Mounted and unmounted design options
• Extremely fast switching speeds
• Silent, vibration-free
• Low-voltage operation
• OEM sizes and shapes
• No mechanical motion
• Stand alone controller available
• Optimized waveforms for driving FLC devices

Technical specifications:

Achromatic FLC Rotator:

Achromatic FLC Shutter:

Achromatic FLC Controller:

OEM Liquid Crystal Variable Retarder

Sintec Optronics is pleased to announce a small, mounted liquid crystal family of products intended for space constrained or OEM applications. By removing the temperature control circuitry, the overall dimensions of the housing can be significantly reduced. For even tighter mechanical constraints, unmounted cells are also available with flying leads or custom connectors.

Features:

• Precision control at lower cost
• Scalable quantities
• Thin housing
• Large clear aperture
• Usable from 450 to 1800 nm

Technical specifications:

MWIR Variable Retarder

Liquid crystal technology for polarization control now extends into the mid IR. Sintec Optronics standard line of polarization controllers can be used for these new variable retarders. They can be custom configured for use as variable attenuators and as polarization rotators.

Features:

• 3600 to 5500 nm transmission
• Non-mechanical polarization control
• Computer controllable
• Useful for variable attenuation

Technical specifications:

UV Liquid Crystal Variable Retarder

Liquid crystal technology for polarization control now extends into the ultraviolet. While standard LC materials are susceptible to UV light damage below 450 nm, Sintec Optronics has designed a new UV-resistant LCVR material capable of operating at lower wavelengths (as low as 350 nm). These parts can be custom configured for use as variable attenuators or polarization rotators and are compatible with our standard line of liquid crystal controllers.

Features:

• Phase of Amplitude modulation of UV spectrum
• Analog modulation
• Non-mechanical polarization control
• Low absorption
• High UV tolerance LC

Technical specifications:

Liquid Crystal Variable Attenuator

Sintec Optronics’ 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 as shown in figure 4-11. 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°). Figure 4-12 shows transmittance as a function of applied voltage. Maximum transmission is dependent upon properties of the LC Variable Retarder as well as the polarizers used in your system. Figure 4-13 shows the transmission of an LC Variable Attenuator optimized for use at 550 nm with crossed polarizers. An unpolarized light source is used for illumination. Extinction ratio is defined as the maximum transmission (LC cell at half-wave) pided by the minimum transmission (LC cell at zero waves). Values exceeding 1000:1 (see figure 4-14) 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. 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.

Features:

• High contrast ratio
• Computer control capabilities
• Continuous control of light intensity

Technical specifications:

Liquid Crystal Polarization Rotator

Our Liquid Crystal Polarization Rotator (LPR) continuously rotates the polarization orientation of a monochromatic, linearly polarized input beam. Our LPR consists of a compensated Liquid Crystal Variable Retarder combined with a zero-order polymer quarter-wave retarder. The fast axis of the liquid crystal variable retarder is oriented at 45° to the slow axis of the quarter-wave retarder and the linearly polarized input must be parallel to the quarter-wave retarder slow axis. Polarization rotation is achieved by electrically controlling the retardance of the Liquid Crystal Variable Retarder, eliminating any mechanical motion. A quarter-wave retarder converts elliptical polarization formed by the Liquid Crystal Variable Retarder to linear polarization. The rotation angle is equal to one-half the retardance change from the Liquid Crystal Variable Retarder. Response time of the LPR depends upon the desired amount of rotation. Small rotations have a longer response time because of a smaller change in the electric field strength. Polarization purity is defined as the ratio of the rotated linear component to the orthogonal component and, on average, polarization purity (or extinction ratio) is better than 150:1. We provide test data including the required voltages corresponding to polarization orientations, in 10° increments, from approximately -40° to approximately 140° rotation. These measurements are taken at ambient temperature for your specified wavelength. Standard Liquid Crystal Polarization Rotators are supplied without an input polarizer. Input polarization direction must be precisely aligned for optimum performance.

Features:

• High power capability
• High polarization purity
• Computer control capability
• 180 degree polarization rotation
• Continuous rotation of linearly polarized light

Technical specifications:

High Contrast Optical Shutter

Our liquid crystal shutter uses twisted nematic liquid crystals to provide a vibration-free mechanical shutter alternative. The twisted nematic liquid crystal switches between a state that rotates the input polarization by 90° with no voltage applied and a state that makes no change in the input polarization with 8 to 10 volts applied. The applied voltage is a 2 kHz AC square-wave. The shutter is supplied with integral dichroic visible polarizers to provide an average extinction ratio of better than 1,000:1. Custom shutters with larger aperture sizes and with wavelength coverage to 2.1 microns are available on a custom basis.

Features:

• High contrast
• No mechanical motion
• Computer control capacity
• No vibration

Technical specifications:

Binary Liquid Crystal Rotator

An Optical Rotator is a two-state device used to rapidly switch between two orthogonal sites of linear polarization. One state has output linear polarization parallel to an input linear polarization state. This occurs when voltage is applied to the rotator. The other state has output polarization orthogonal to the input polarization and occurs when no voltage is applied. Sintec Optronics manufactures and sells liquid crystal based Optical Rotators for applications requiring active timing control of beam transmittance by using them in combination with high quality polarizers. Key features of our Optical Rotators include high-speed binary operation, high purity linear polarized output, and maximum extinction ratio performance. Since these devices are solid state – undesirable mechanical motion, associated noise, and vibration problems are eliminated. Binary LC Rotators deliver optimum extinction ratio performance, often greater than 10,000:1 across the visible wavelength range, when used with high quality polarizers. Even higher extinction performance is achieved over narrower bandwidths or for single laser line applications. Up to 100% duty cycle operation is standard. This Rotator has a broad operating temperature range, designed to meet applications requiring low cost components with negligible impact on performance.

Features:

• High polarization purity
• Silent, vibration-free
• Low-voltage operation
• Broad thermal range
• Faster switching speeds than LCVRs

Technical specifications:

High Speed Liquid Crystal Variable Retarder

Sintec Optronics newest liquid crystal (LC) product, the high speed LC variable retarder (HS LCVR) has a 10X speed improvement over our award winning standard LCVR. The sub-millisecond speeds are achieved without the 50/50 duty cycle drive scheme required by our ferroelectric liquid crystal components, but are nearly as fast. The new LCVR uses nematic liquid crystal materials to electrically control polarization and provide tunable retardation by changing the effective birefringence of the material with applied voltage, thus altering the input polarized light to any chosen elliptical, linear or circular polarization. Our precision HS LCVR requires unique fabrication and assembly steps. We construct these retarders using optically flat fused silica windows coated with our transparent conductive Indium Tin Oxide (ITO). Our ITO coating is specially designed for maximum transmission from 400 – 700 nm. Liquid Crystal Variable Retarder response time depends on several parameters, including layer thickness, viscosity, temperature, variations in drive voltage and surface treatment. Liquid crystal response time is proportional to the square of the layer thickness and therefore, the square of the total retardance.

Features:

• Sub-millisecond speeds
• Standard LC Drive Schemes
• Includes heated housing
• Precision non-mechanical retardation control

Technical specifications:

Analog Liquid Crystal Controller

Sintec Optronics is excited to announce the release of the Model B1010, our new Analog Liquid Crystal Controller. This liquid crystal (LC) driver is designed to integrate with any single (standard) Meadowlark Optics LC device currently offered as well as any nematic Liquid Crystal device compatible with the specifications listed. Independent voltage settings allow easy and repeatable selection of two retardance values. Often, it is desirable to modulate between the two states. For example, switching between quarter-wave and three quarterwave retardance changes linearly polarized light between left and right circular. A manual toggle allows easy switching between two states. Banana jacks between the knobs allow for continuous voltage monitoring without interfering with LC device connections. Each Sintec Optronics Liquid Crystal Variable Retarder is supplied with a plot of its actual retardance versus voltage. Using your Model B1010 Controller and this retardance plot ensures accurate retardance to voltage correlation.

Features:

• Convenient, stand-alone bench top operation
• Versatile-compatible with all standard Sintec Optronics LC devices and other nematics
• Out-of-the-box functionality. Sets up in minutes
• Optional battery supply for short term use
• Banana jacks allow for easy multimeter attachment

Technical specifications:

Two Channel High Voltage Interface

Our two Channel High Voltage Digital Interface is designed for independent high precision computer control of up to two Sintec Optronics Swift LC liquid crystal devices at one time. The D3060HV Package includes all the functionality of the D3050 plus the high voltage circuitry necessary for Swift LC devices. Also included is capability for temperature monitoring and control on one channel. The Advanced Package allows the amplitude of the 13 kHz square wave output to be driven either by an external signal supplied to a front panel connector or specific CellDRIVE generated waveforms including sinusoidal, square, triangle, sawtooth and transient nematic effect waveforms. Additional functions include the capability to output a sync pulse on a front panel connector at desired points in the CellDRIVE generated waveforms and the ability to save/restore all CellDRIVE settings to/from a file.

Features:

• USB or RS232 interface
• C++ code examples (all required libraries included)
• Compact and simple to use
• Microsoft® HyperTerminal configuration file included
• Independent control of voltage levels on two channels to 10 mV resolution
• Includes National Instruments LabVIEW™ Virtual Instrument drivers to interface with custom software

Technical specifications:

Liquid Crystal Digital Interface Controller

The new D5020 Liquid Crystal Digital Interface is the next generation in the evolution of Sintec Optronics Liquid Crystal Controllers. The Digital Controller is designed for user functionality and productivity. The D5020 provides a “set and go” function that allows the controller to run autonomously without a computer. Controlling multiple Liquid Crystal cells has never been easier. CellDRIVE 5000 software provides a separate sync output for each channel as well as temperature sensing and control on both channels. The 2kHz square wave output can be amplitude modulated with sinusoidal, square, triangle, sawtooth and transient nematic effect waveforms.

Features:

• Two channels of voltage and temperature sensing & control (TSC)
• USB powered (unless using TSC)
• Waveforms generated internally
• Independent SMB I/O Connectors for each channel
• Multiple external control options
• Includes USB and LabVIEW™ code example

Technical specifications:

LC Temperature Controller

The Sintec Optronics TC3051 is a single channel, microprocessor based temperature controller specifically designed to work with Meadowlark Optics’ liquid crystal devices equipped with the Temperature Sensing and Control (TSC) option. The TC3051 requires minimal setup: connect the included power supply, connect the temperature control cable to both the TC3051 and the liquid crystal device and turn the power on.

Features:

• Stand alone
• LED display
• 1 channel temperature control

Technical specifications:

Ferroelectric Liquid Crystal Controller

The FCS010 is a two‐channel liquid crystal controller specifically designed to drive our ferroelectric liquid crystal shutters and rotators. It has two short‐circuit protected output channels driven 180 degrees out of phase. The pre‐configured controller waveforms are optimized for FLC devices. We can tailor the waveform to your specific needs based on application and purchased FLC device. The drive waveform is output through SMA connectors. This controller is 100% RoHS compliant and is powered by a separate 12V international power supply.

Features:

• Automatically DC balances
• External modulation
• 10V output
• Gate input
• Drive I/O
• Frequency range 1Hz - 10kHz

Technical specifications: