Choosing a spectrometer for a compact OEM instrument requires balancing several requirements. The key parameters to evaluate are physical size, spectral range, spectral resolution, sensitivity, measurement speed, optical and electronic integration, and OEM customization requirements.
1. Physical Size
For a compact OEM instrument, physical size can be a critical design constraint. A smaller spectrometer can make it possible to integrate spectral measurement into instruments where a conventional spectrometer would be too large.
When choosing a compact spectrometer, consider not only its overall footprint but also how it fits within the mechanical and optical architecture of the instrument.
2. Spectral Range
Start by defining which wavelengths the instrument needs to measure. The spectrometer should cover the required range for the application, with enough margin for the intended measurement.
For example, PEBBLE VIS covers the 360–830 nm visible range.
3. Spectral Resolution
The required resolution depends on the spectral features you need to distinguish. Applications that require identification of narrow spectral peaks may need higher resolution, while broader spectral features may not require the same level of resolution.
When selecting a spectrometer, consider the required resolution together with the spectral range and measurement objective.
4. Sensitivity
A spectrometer needs to collect enough optical signal for the intended measurement. Detector characteristics, optical design, numerical aperture, and available light levels can all affect measurement performance.
For an OEM instrument, sensitivity should therefore be evaluated in the context of the complete optical system, rather than as an isolated specification.
5. Measurement Speed
If the instrument measures changing signals or operates in an automated environment, acquisition speed can be an important consideration.
The required speed should be matched to how quickly the optical signal changes and how the OEM instrument is expected to operate.
6. Optical Integration
How will light enter the spectrometer?
The optical input configuration and numerical aperture can affect how efficiently the spectrometer collects light from the rest of the optical system. Depending on the instrument design, factors such as free-space or fiber-coupled input may also influence the integration approach.
7. Electronic Integration
The spectrometer also needs to communicate with the instrument’s electronics.
When choosing a spectrometer for OEM integration, consider the available electrical interfaces and how spectral data will be acquired and processed by the instrument.
8. OEM Requirements
Finally, consider whether a standard spectrometer fully meets the requirements of the final instrument.
For OEM applications, customization and development support can be important when the required specifications, mechanical constraints, or integration requirements differ from standard configurations.
A Compact Example: PEBBLE VIS
For applications where physical space is a critical constraint, PEBBLE VIS from Ibsen Photonics is an example of a compact OEM spectrometer designed for visible-range applications.
Its 20 × 15 × 8 mm footprint, 360–830 nm wavelength range, 5.2 nm typical resolution, free-space or SMA optical input, and SPI or USB electrical interfaces provide several options for integration into compact instruments. Ibsen also offers customization when standard configurations do not match an OEM’s requirements.