CUT-ON FILTER      

LONG PASS CUT-ON FILTERS
Long pass cut-on filters are used to prevent higher order radiation from the grating monochromator from entering the Sample Compartment. Optometrics' long pass cut-on filters are cored from selected color glasses which transmit radiation above and block radiation below a specified wavelength. The wavelength interval (transition interval) from blocking to maximum transmission is sharp, typically 25 to 35 nm. Long pass cut-on filters are identified by a cut-on wavelength, i.e., the wavelength at 50% of maximum transmission.

Long pass cut-on filters have an average high transmission of 85% from 15 to 20 nm above their cut-on wavelength to 2000 nm. Attenuation of radiation below the cut-on wavelength is due to absorption of the colorants in the glass and the thickness of the glass. Superior blocking in Optometrics' filters (0.001%) is due to the use of 3mm-thick color glass.

Optometrics' long pass cut-on filters are all epoxied in a black metal ring for easy mounting and handling and are 25.4 mm dia. x 9.65 mm thick. The cut-on wavelength is marked on all filters. Designed to mount directly in the Optometrics' sample chamber.

GENERAL SPECIFICATIONS

LONG PASS CUT-ON FILTERS

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STEPPING MOTOR CONTROLLER
The PCM-02 is a modular component, ideally suited for driving the Optometrics line of Scanning Digital Monochromators.

Using a computer, the operator can move the monochromator to a specific wavelength and scan over a wavelength range. The PCM-02 application program can be used with Windows® 95, 98, 2000, XP and Vista.

When a terminal is used to drive the monochromator, the user can access over 25 commands that control a variety of operations of the grating drive (e.g. including the distance to be moved, the initial and final velocities of the move, the acceleration, the time period for pauses, etc.). Commands can be sent at any time, even when the motor is operating. The motor controller board includes over 2,000 bytes of non volatile memory to store complex motion-control programs.

Six Scanning Digital Monochromators are available for use with the PCM-02. Each monochromator is fitted with a pair of entrance and exit slits specified by the user. Additional slits can be ordered separately.

Jump to details of our Monochromator models.

GENERAL SPECIFICATIONS

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DETECTOR MODULES
Optometrics' Silicon Detector Modules are designed for direct mounting on Mini-Chrom monochromators or in either aperture of the standard Sample Compartment.
The modules are compact, low cost, simple to mount and require no user alignment. The Silicon Detectors have a wide spectral response (200 nm to 1100 nm) with a peak response at approximately 900nm. The detectors cover the UV-VIS-NIR spectral region and are used extensively as components in analytical and biomedical instrumentation, and in research, teaching and quality control. In addition to their wide spectral response, photo cells have excellent linearity and signal-to-noise ratios.

The Detector Module consists of a mounted silicon photodiode, an integral low noise, high speed and exceptionally high stability operational amplifier and a slit assembly in a rugged housing. Mounting is facilitated by a pair of banana plugs on the slit assembly. When exposed to electromagnetic radiation of sufficient energy, photo cells generate an electrical signal. The signal is the result of a photon-induced difference in potential between the P and N layers within the photo cell, i.e. the photo voltaic effect. The signal is proportional to the energy of the impinging radiation and varies as a function of wavelength. The Silicon Detector Module incorporates a photocell with low dark current, a fast response time, a quartz window and thin P-layer for an enhanced response to ultraviolet radiation.

A slide switch enables the selection of the time constant and "fast" for the recording (RS) spectrophotometer and computer data acquisition.

Power to the modules (± 15V DC) can be supplied with a wall-mounted power supply (for 115V AC) or by an external power supply (for 230V AC).

Jump to details of our Monochromator models.

SPECIFICATIONS

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VARIABLE WAVELENGTH FIBER OPTIC MODULE
Configure your own Optometrics' Variable Wavelength Fiber Optic Module - a rugged, low-cost compact instrument that produces monochromatic light out of a fiber optic bundle. Operation is as simple as turning on the lamp and rotating a dial until the desired wavelength appears on the four-digit counter. The module can be used for remote spectroscopic sensing or in any application requiring monochromatic radiation that cannot be obtained easily by conventional methods.

The module is comprised of a 20 watt tungsten halogen source, a digital or scanning digital monochromator and a five-foot fiber optic bundle. The fiber bundle end is formed into a rectangular array that plugs directly into the monochromator, functionally replacing the exit slit. It is supplied with a 600 micron slit assembly for use on the entrance side. The other end terminates in a conventional circular bundle. Choose either the Digital Mini-Chrom or the Scanning Digital Mini-Chrom monochromator and a Stepping Motor Controller.

View details of our Monochromator models.

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TUNABLE LIGHT SOURCES

Tunable light sources are used to maximize throughput in the visible region of the spectrum. They are used to study wavelength-dependent chemical, biological, and physical changes or properties. The sources can also be used in color analysis and reflectivity measurements of products for aesthetic purposes.

The filament of a 20W tungsten halogen lamp is imaged so that it exactly fills the entrance slit of a Mini-Chrom monochromator. Surprisingly, as higher power lamps have larger filaments, most of the extra energy never makes it through the entrance slit and lamps with significantly higher wattage will not produce significantly higher throughput.

By turning the knob on the manual version, or using software control on the motorized version, the grating is rotated to allow only a few nm of light to pass through the fiber optic adapter or cable. Optometrics offers a wide range of grating choices for its tunable light sources to provide optimum band pass selectivity and throughput.

The lamp used in the TLS series has usable spectral energy between 360 nm and 2000 nm. However, no one grating can give adequate performance over this range.

Optometrics offers versions optimized for the visible spectrum 360 nm to 800 nm and others for the near infrared. These components are especially useful when coupled with our variable wavelength fiber optic modules.

For most illumination applications, band passes of 5 nm or narrower are considered to be high resolution. Band passes of 10 nm or less are rarely needed in colorimetry or photochemistry.

Optometrics offers three models: the TLS-6 with a 6 nm band pass, the TLS-10 with a 10 nm band pass and the TLS-25 with a 25 nm band pass when used with the standard 600 micron entrance slit and the optional 7-2505 or 7-2506 fiber optic cable. Power increases with band pass. Typically users will trade band pass for throughput, i.e. use the widest band pass possible that will not affect the quality of the measurement.

Typical power output using the 7-2505 fiber bundle and a 600 μ entrance slit. The power and band pass will increase or decrease proportionally to the change in effective entrance and exit port apertures.

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