Information about the Ocean Optics Spectrometer
The following information was copied and modified from the WEB site for Ocean Optics
http://www.oceanoptics.com/homepage.asp
USB2000 Specifications
How the USB2000 Works
The following diagram illustrates the movement of light through the optical bench of the USB2000 Spectrometer. You can customize the items marked with an asterisk (*) when ordering the USB2000.
Note: The optical bench has no moving parts that can wear or break. Ocean Optics secures all components in place permanently at the time of manufacture.
Figure 2-1: USB2000 Spectrometer with Components
The USB Component Table on the following page explains the function of each numbered component in the USB2000 Spectrometer diagram (Figure 2-1).
USB2000 Component Table
1 SMA Connector
The SMA Connector secures the input fiber to the spectrometer. Light from the input fiber enters the optical bench through this connector.
2 Slit*
The Slit is a dark piece of material containing a rectangular aperture, which is mounted directly behind the SMA Connector. The size of the aperture regulates the amount of light that enters the optical bench and controls spectral resolution.
You can also use the USB2000 without a Slit. In this configuration, the diameter of the fiber connected to the USB2000 determines the size of the entrance aperture.
Only Ocean Optics technicians can change the Slit.
3 Filter*
The Filter is a device that restricts optical radiation to pre-determined wavelength regions. Light passes through the Filter before entering the optical bench. Both bandpass and longpass filters are available to restrict radiation to certain wavelength regions.
Only Ocean Optics technicians can change the Filter.
4 Collimating Mirror
The Collimating Mirror focuses light entering the optical bench towards the Grating of the spectrometer.
Light enters the spectrometer, passes through the SMA Connector, Slit, and Filter, and then reflects off the Collimating Mirror onto the Grating.
5 Grating*
The Grating diffracts light from the Collimating Mirror and directs the diffracted light onto the Focusing Mirror. Gratings are available in different groove densities, allowing you to specify wavelength coverage and resolution in the spectrometer.
Only Ocean Optics technicians can change the Grating.
6 Focusing Mirror
The Focusing Mirror receives light reflected from the Grating and focuses the light onto the CCD Detector or L2 Detector Collection Lens (depending on the spectrometer configuration).
7 L2 Detector Collection Lens*
The L2 Detector Collection Lens (optional) attaches to the CCD Detector. It focuses light from a tall slit onto the shorter CCD Detector elements.
The L2 Detector Collection Lens should be used with large diameter slits or in applications with low light levels. It also improves efficiency by reducing the effects of stray light.
Only Ocean Optics technicians can add or remove the L2 Detection Collection Lens.
8 CCD Detector (UV or VIS)
The CCD Detector collects the light received from the Focusing Mirror or L2 Detector Collection Lens and converts the optical signal to a digital signal.
Each pixel on the CCD Detector responds to the wavelength of light that strikes it, creating a digital response. The spectrometer then transmits the digital signal to the OOIBase32 application.
USB2000 Specifications
The following sections provide specification information for the CCD Detector in the USB2000, as well as the USB2000 Spectrometer itself.
CCD Detector Specifications
Detector:
Sony ILX511 linear silicon CCD array
Number of elements:
2048 pixels
Pixel size:
14 μm x 200 μm
Pixel well depth:
62,500 electrons
Signal-to-noise ratio:
250:1 (at full signal)
A/D resolution:
12 bit
Dark noise:
2.5 RMS counts
Corrected linearity:
>99.8%
USB2000 Spectrometer Specifications
Dimensions:
89.1 mm x 63.3 mm x 34.4 mm
Weight:
190 g (without cable)
Power consumption:
90 mA @ 5 VDC
Detector range:
200-1100 nm
Detector:
2048-element linear silicon CCD array
Gratings:
14 gratings; UV through Shortwave NIR
Entrance aperture:
5, 10, 25, 50, 100 or 200 mm wide slits or fiber (no slit)
Order-sorting filters:
Installed longpass and bandpass filters
Focal length:
f/4, 42 mm (input); 68 mm (output)
Optical resolution:
~0.3-10.0 nm FWHM (depending on grating and size of entrance aperture)
Dynamic range:
2 x 108 (system); 2000:1 for a single scan
Stray light:
<0.05% at 600 nm; <0.10% at 435 nm; <0.10% at 250 nm
Sensitivity (estimate):
400 nm – 90 photons/count; 600 nm – 41 photons/count; 800 nm – 203 photons/count
Fiber optic connector:
SMA 905 to single-strand optical fiber (0.22 NA)
Data transfer rate:
Full scans into memory every 13 milliseconds
Integration time:
3 milliseconds to 65 seconds
Fiber optic connector:
SMA 905 to single-strand optical fiber (0.22 NA)
Operating systems:
Windows 98/Me/2000/XP when using the USB interface on a desktop or notebook PCs
Any 32-bit Windows operating system when using the serial port on desktop or notebook PCs
Windows CE 2.11 and above when using the serial port on palm-sized PCs
Efficiency Curves for Gratings - The CH 461 stations have grating H2
