Conoptics’ series of electro-optic deflectors are the most efficient mechanisms for changing the angle of a laser beam. Conoptics EOD’s can scan a laser beam over a range of angles, or control the output angle of a laser beam with great accuracy. We employ a quadrapole electric field in an electro-optic material to produce a linear refractive index gradient proportional to the applied signal voltage.

Specifications

The angular deflection of our E-O Deflectors is small but has rapid random access response and is extremely precise. Unlike acousto-optic deflectors, the intrinsic random access response of an electro-optic deflector is the optical rather than acoustic transit time. In practice, however, E-O Deflectors appear as capacitive loads and the response is driver limited. The precision with which a laser beam can be located, for all intents and purposes, is equivalent to the precision with which a voltage level can be applied to the device. Since operation is based on an index gradient, variations due to ambient temperature changes are reduced to second order effects. Similarly, unlike acousto-optic deflectors in which the deflection angle is proportional to the optical wavelength, the deflection angle of an electo-optic deflector is a function of the index dispersion and is relatively constant over the wavelength range of operation.
Other advantages of an E-O Deflector over an acousto-optic device include the fact that the entire beam is deflected. The transmission efficiency is limited only by the Fresnel reflections, absorption, and scattering losses in the cell and is not a function of the deflection mechanism.

Furthermore, E-O Deflectors are “straight through” devices, that is, the beam is deflected about the un-deflected zero applied signal position. This is in contrast to acousto-optic devices which have a large angular offset to the center of the deflection range and require that RF be maintained on the cell when the beam is in the quiescent position.

The deflection angle, symbol1 of an E-O Deflector is given by:

formula1

Where K is a constant determined by the electro-optic material used, V is the applied voltage, L is the active length of the device, and ais the aperture diameter. Translating deflection angle to the number of resolvable spots:

formula2

Where a diffraction limited Gaussian beam of a diameter “a” and wavelength “i” of symbol2 is assumed and beam clipping losses are ignored. Since V/a is limited by the internal breakdown voltage (approx.1000v/mm for fluid filled units), once an electro-optic material and operating wavelength have been chosen, the active length is the only parameter remaining to increase the number of resolvable spots. Note that the equation given above is highly idealized and that “V” and “a” deserve considerable consideration because they determine the difficulty of electronics design and crystal fabrication.

Conoptics offers several standard electronics drivers which may be use with our E-O Deflectors. Many operational requirements, however, are more easily satisfied by modifications and special versions of the 310A and drivers. The most common changes are larger aperture diameters, operation in the UV and IR, and higher output voltage drivers with special waveforms. Construction of X-Y systems by coupling two deflectors with an intermediate polarization rotator is also common. Addition of a sensor and feedback loop driver allows the construction of a beam pointing stabilizer.

List of Deflectors

Model 310A

Aperture (mm) 2.5mm
Deflection Efficiency 1.5 micro-radians/volt
Capacitance, pf 100
Standard Spectral Range 400nm-to-750nm
Length (mm) 118mm
UV / DUV options Yes

Model 311A

Aperture (mm) 2.5mm
Deflection Efficiency 3.0 micro-radians/volt
Capacitance, pf 185
Standard Spectral Range 400nm-to-750nm
Length (mm) 219mm
UV / DUV options Yes
Collinear Configuration Center In/Center Out

Model 312

Aperture (mm) 2.7mm
Deflection Efficiency 0.6 micro-radians/volt
Capacitance, pf 50
Standard Spectral Range 400nm-to-1100
Length (mm) 71mm
UV / DUV options Yes
Collinear Configuration Center In/Center Out

Model 312-2

Aperture (mm) 2.7
Deflection Efficiency 1.2 micro-radians/volt
Capacitance, pf 100
Standard Spectral Range 400nm-to-1100nm
Length (mm) 125mm
UV / DUV options Yes
Collinear Configuration Center In/Center Out

Model LTA 4-Crystal

Aperture (mm) 2.0mm
Deflection Efficiency 4 micro-radians/volt
Capacitance, pf 40
Standard Spectral Range 700nm-to-1000nm or 1000nm-to-2000nm
Length (mm) 110mm
UV / DUV options No
Collinear Configuration Center In/Center Out

Amplifier Key Features:

Model 302RM Amplifier

Cabinet Driver and power supply in single cabinet
Test Feature Built-in test feature allows testing for max transmission of Pockel Cell without adjusting bias voltage
Input Impedance Choice of amplifier input impedance by rear panel switch (50ohm/1K ohm)
DC Bias Improved DC biasing of Pockel Cell provides greater linearity at higher bias voltages
Voltage Range +/- 450VDC controlled by ten-turn front panel pot. Digital meter monitors differential bias applied to E.O. Modulator
Linearity 10bits referenced to full scale (.1%)
Bandwidth DC to >200Khz with 90pf load and 3M (RG-62) cables
Max. Output Drive Level 750VP-P into 90pf load
Amplifier Input Signal 2VP-P max into 50/1K ohms delivers 750VP-P out
Input Signal Format Options include Unipolar positive, negative or bipolar
Input Power (AC) 60W typical. Input power is both load (modulator) and frequency dependent.
Dimensions 19″ Rack Mountable, 5.25″H(133mm) (3U) x 14″D (356mm)
Cooling Forced air
Operating Environment Designed for laboratory use (indoor only) Temperature range +5deg C to +50deg C ambient Humidity 20%-80% RH up to 32deg C Altitude <3000M
Weight 20lbs (9.07kg)

Model 412 Dual Amplifier

Cabinet Driver and power supply in single cabinet
Input Impedance Choice of amplifier input impedance by rear panel switch (50ohm/1K ohm)
Gain 375V/V Each Amplifier
Max. Output Drive Level 750V P-P, each amplifier, driving 60pf load, 3m RG-62 cables
Detected Rise/Fall Time Typically 2.5us driving 60pf with 3m RG-62 coax
Input Signal Format Options include Unipolar POS/NEG or bipolar set by rear-panel slide switch
Input Power (AC) Typically 70W (load and frequency dependent)
Dimensions 19″ Rack Mountable, 5.25″H(133mm) (3U) x 14″D (356mm)
Cooling Forced air
Operating Environment Designed for laboratory use (indoor only) Temperature range +5deg C to +50deg C ambient Humidity 20%-80% RH up to 32deg C, Altitude <3000M
Weight 20lbs (9.07kg)

Model 25D Amplifier

Cabinet Driver and Power Supply in same cabinet
Input Impedance 50ohms
Gain +/- 400vDC
Max. Output Drive Level 175V
Detected Rise/Fall Time 8ns
Input Signal Format TTL or Analog
Input Power (AC) 300W
Dimensions 45cm W x 44cm L x 17.5cm H
Cooling Forced Air
Operating Environment Designed for laboratory use (indoor only)
Weight 32lbs

Related Products

M312-1

M312-2

Model 310A Outline Drawing

Model-310A-Outline-Drawing

Model 320 Nutator Deflector

Model-320-Nutator-Deflector

Model 412 Deflector Cutout