We believe you should have full control and maximum flexibility when configuring your VIS spectrometer. That’s why we offer so many build-to-print options for range, resolution, detector cooling, and sample coupling – backing each with our advice and experience. Learn more about each below, or contact us to discuss the best options for your application.
SLIT WIDTH: Defining Resolution
Sensitivity and resolution are competing factors when choosing slit size. A larger slit allows more light to enter the spectrometer, increasing sensitivity for low-light applications such as fluorescence. Resolution improves, however, as slit width is reduced (though not always linearly). We offer 25 and 50 μm slits for our VIS spectrometer, and can advise on the best choice for your application. Due to the high sensitivity of our low f/# spectrometer designs, it is often possible to use a smaller slit width than would be required with a typical f/4 spectrometer, allowing you to achieve higher resolution.
SAMPLE COUPLING: Fiber or free-space?
How you interface with your sample can vary depending on the type of sample, environment, and the goals of your measurement. Whether you need to sample remotely or create a compact design, we have options for you. The sampling coupling option is chosen at time of spectrometer order, but can be exchanged by special order.
Fiber coupling to spectrometer (-SMA)
Using a fiber to route light to and from your sample is both flexible and convenient, and can help to minimize interference from ambient light in the measurement path. To get superior signal and ultra low background from our f/1.3 design WP VIS spectrometer, we recommend the use of matched NA fibers (0.36-0.39). The image at left shows the SMA connector input to our spectrometer. A custom FC/PC input is available upon request (-FC).
Free-space coupling to spectrometer – open slit (-FO)
Coupling light directly into a spectrometer slit gives you the freedom to design your own sampling optics, controlling parameters like sampling spot size and working distance. This approach is good for creating compact systems while minimizing coupling losses due to fibers, and is ideal for research & OEMs. Our WP VIS spectrometer has a 0.36 NA input (shown at left), accepting light up to 21° off axis (42° full angle).
Free-space coupling to spectrometer – collimating lens (-FL)
Our collimating lens input option allows you to employ free-space coupling to your spectrometer with a more limited field of view. The integrated collimating lens is perfectly matched to the WP VIS 0.36 NA design to focus light onto the slit. This option is compatible with our quick-fit cuvette holders used for absorption, transmission, and fluorescence measurements. It can also be used to couple directly to a microscope, other optics, or for directional sensing.
DETECTOR COOLING: Controlling noise
We offer ambient and TEC-regulated detectors for the WP VIS spectrometer, allowing you to balance your required signal to noise ratio (SNR) and temperature stability with cost for the best possible value.
An uncooled detector is often adequate for many basic spectroscopy applications, but for uncontrolled environments, a thermoelectrically regulated (TEC-regulated) detector offers better noise floor stability. Contact us to discuss the right choice for your application.
AMBIENT (-A) | TEC-REGULATED (-R) | |
| Detector temperature | Room temp (≈ 25°C) | 10°C |
| Benefits | Most cost effective option for quick measurements; lower power consumption | Fixed dark noise (better measurement reproducibility) |
| Signal to noise | Good SNR high throughput detector | Improved SNR compared to ambient detector |
| Applications | Best for teaching and lab environments | Great for variable environments |
