1250C-2BS-943A
NIR Acousto-Optic Deflector
The 1250C-BS-943A is a beam steered, medium resolution, high speed AO deflector designed for use with laser diodes operating in the 750-850nm wavelength region*. In addition, the expanded RF bandwidth and large active aperture of this device are well suited to double-pass NIR frequency shifting applications.
SPECIFICATIONS
Operating Wavelength:
750-850nm *
Interaction Material:
PbMoO4
Laser Wavelength:
800nm *
Acoustic Velocity:
3630 m/s
Active Aperture:
2 x 6mm
Centre Frequency:
185 MHz
RF Bandwidth:
120MHz
Diffraction Efficiency:
>30% @ 3.2 Watts (total)
Input Bragg Angle @ fc:
19.3 mrad
Separation Angle @ fc:
38.6 mrad
Scan Angle:
26.4 mrad
Input Impedance:
50ohms (nominal)
Access Time (τ):
1.6usec
τ△f Resolution:
190 spots
Static Insertion loss:
≤ 5% (750 - 850nm)
* Please contact Isomet for other wavelengths
RECOMMENDED RF DRIVE ELECTRONICS
D325-2BS or D335-2BS VCO deflector driver
or
iMS4-L(or P)-Fx2 synthesizer with 805C series amplifier (x2)
BRAGG ANGLE AND BEAM STEERING
First order deflection efficiency is maximised when the angle (θ) of the input laser beam satisfies the Bragg condition:
As the drive frequency is swept about the centre frequency fc so the efficiency will vary due to the Bragg angle mismatch. To minimize this effect the acoustic signal in the AO material can be made to track the optimum Bragg conditions over a wider range of frequencies. This ‘beam steering’ technique requires an array of electrodes on the device transducer. By applying an appropriate delay between the electrodes the resultant phase change steers the angle of the transmitted acoustic beam from the transducer in relation to the applied drive frequency.
A typical response for 1250C-2BS-943 with D325-2BS driver is shown below. The optimum RF drive power is proportional to the wavelength^2. At NIR wavelengths this power can exceed the maximum recommended input level. The result is a reduction of the overall efficiency across the scan to around 30% at 830nm as shown overleaf.
OUTLINE DRAWING
商品属性 [波长] 750-850nm [活跃孔径] 2 x 6mm [光学材料] PbMoO4