Stories & Features
Penta-Band Case Study
Nov 10, 2025
by
IDEX Health & Science
From Problem to Performance: A Custom Filter that Transformed Imaging Quality
When a customer came to us with a persistent imaging problem, we saw an opportunity, not just to solve it, but to redefine what is possible to achieve and measure in optical filter performance.
The customer was using a competitor’s filter in a multi-band fluorescent imaging system using laser excitation (trace shown in red in the figure above). The filter performance was adequate in theory, with the laser wavelengths falling within the blocking regions shown shaded in the figure above. In practice, however, the results were disappointing: Image backgrounds were not consistently black, and blocking performance varied significantly between instruments and over time.
The culprit? Inconsistent optical density (OD) values across critical laser wavelengths, leading to unpredictable image quality with unacceptable noise levels.
The Hidden Problem: What Traditional Tools Couldn’t See
The filter’s blocking notches are narrow and deep—too narrow and deep, in fact, for traditional spectrophotometers to measure accurately. That’s where our proprietary KolaDeep™ Spectral Measurement System came to the rescue, as it is uniquely capable of resolving ultra-deep blocking levels, even when high-transmission passbands are tightly adjacent.
Our measurements revealed several issues. For example, at around 747 nm there is a sharp spike in blocking (see the rightmost arrow in the figure). If the laser wavelength aligns with the peak of that spike, the filter achieves only OD 5 blocking. Just a few nanometers to the red, blocking jumps to OD 7—resulting in a 100 times darker background. These inconsistencies were present across multiple bands and explained the customer’s imaging challenges.
The Semrock Solution: Precision Engineered for Performance
In response, IDEX Health & Science designed a superior Semrock filter (performance shown in green in the figure) that delivers:
- OD > 8 blocking in every laser channel
- Steeper edges across all nine transitions
- Wider passbands in all five channels
These improvements mean brighter fluorescence signals, deeper contrast, and dramatically reduced background noise. Users can now shorten exposure times for high-throughput imaging or extend them to detect faint signals, without sacrificing image quality.
Proof of Performance
We measured the newly manufactured filter; see the blue trace in the figure. The results? OD 9 blocking levels, so deep they hit the noise floor of our measurement system. That is not just good—it is exceptional.
The final validation came from the customer: All issues were resolved. The customer reported brighter images, higher contrast, and consistently deep black backgrounds across all instruments in which this filter was deployed.
Why Work with IDEX Health & Science?
This is not just a success story—it’s a blueprint for collaboration. We bring together world-class expertise to designing our Semrock optical filters, precision manufacturing, and advanced measurement, to ensure that every filter meets its exacting performance specifications. From concept to production to validation, we partner with you to solve complex imaging challenges. Whether you're advancing fluorescence imaging or developing next-generation diagnostic tools, we deliver filters that strike the perfect balance of performance, quality, and cost.
Precision meets Partnership: Let’s Innovate Together.