Thin films deposition monitor AOS-4S (Ref.No. VPOL- aosS) and AOS-4Sir (Ref.No. VPOL-aosSir)

Desk-top spectrophotometer AOS-4SL
( Ref.No.VPOL- aosL)

The AOS-4S acoustooptic spectrophotometer is designed both as desk top spectrophotometer AOS-4SL and as optical thin films deposition optical monitors AOS-4S and AOS-4Sir.
The main purpose of the device is to realize high-efficient method of optical coating run spectrum monitoring in real time. It is achieved by measuring reflectance or transmittance of the coating at high-speed wavelength scanning within a fixed spectrum region. In so doing, most detailed on-line information on a coating of an arbitrary type can be obtained at any moment of the production run. The spectrophotometer also allows to use some operation modes with a fixed wavelength:single-wave extremum monitoring for quarterwave coating, single-wave level monitoring, and two-wave merit function monitoring.
The device can also be used as a desk-top spectrophotometer for lab and industrial applications. Main advantages of the spectrophotometer are as follows:

• high-speed scanning within a wide spectrum range;
• high precision and sensitivity of the photometric procedure;
• absolute wavelength setting without preliminary calibration;
• efficient noise suppression.

AOS-4S thin films deposition optical monitor

The AOS-4S acoustooptic spectrophotometer consists of:

• acoustooptic monochromator comprising tunable acoustooptic filters and photodetectors;
• control unit that produces radio-frequency voltage to control the wavelength tuning, performs the initial processing of the recorded signal and supports interface with the control computer.

The spectrophotometer operates only under the control of an IBM PC compatible computer using MS DOS or Windows operating systems. Software is an integral part of the spectrophotometer, it sets a spectrophotometer operation mode, controls wavelength tuning, processes the recorded signal, calculates coating characteristics, represents experimental and calculated data on the display and aaves them on a appropriate media.
These devices have some advantages by comparison with classic gratings spectrophotometers. These advantages are essential for the device to be used in deposition system. They are as follows:

• electronic frequency scanning is practically inertialess;
• signal modulation can be performed by RF-signal modulation and thus there is no need in mechanical modulators;
• the acoustooptic filter is a non-slit device, and this fact facilitates its matching with light sources and optical components of the vacuum chamber and provides larger illumination.

• AOS-4SL
• AOS-4S
• AOS-4Sir

• at 408 nm wavelength:
• at 633 nm wavelength:
• at 1014 nm wavelength:

• at 370...720 nm range:
• at 720...1175 nm range:

• reflectance (R in %): at 400...1100 nm range:
• transmittance (T in %): at 400...1100 nm range:

• monochromator:
• control unit: