BH-A29 Near-infrared longpass / cold-mirror filter

BH-A29 is a near-infrared longpass / cold-mirror filter. A high-transmission region is shown at approximately 747-1200 nm.

Measured wavelength range: 300-1200 nm
Peak transmission: ≈ 95.8% at 1025 nm
Transmission ≥80%: 747-1200 nm
Transmission ≤5%: 300-674 nm
380-410 nm: 2.504% average transmission
Custom options: Wavelength response, dimensions and operating conditions

Values shown are sample measurements. Final specifications are agreed for your order.

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Near-infrared longpass / cold-mirror filter (BH-A29)

BH-A29 is a near-infrared longpass / cold-mirror filter. A high-transmission region is shown at approximately 747-1200 nm. Consider it when you need to pass longer wavelengths and reduce shorter-wavelength light within the measured range.

Optical performance

Measured wavelength range: 300-1200 nm. Performance outside this measured interval is not established by this curve.
Selected regions at or above 80% transmission: 747-1200 nm. Approximate measured intervals.
Selected regions at or below 5% transmission: 300-674 nm. Measured sample intervals; confirm the required blocking for your order.
Peak transmission: Approximately 95.8% at 1025 nm. Peak wavelength is not the same as a defined centre wavelength.
Average measured transmission, 380-410 nm: 2.504%. Calculated from the factory sample data.
Average measured transmission, 430-650 nm: 0.734%. Calculated from the factory sample data.
Average measured transmission, 800-1200 nm: 94.020%. Calculated from the factory sample data.
Customization: We can customize stock and sample-book designs. Tell us the wavelength response, size and operating conditions you need.

These values come from the measured samples and help you choose a starting design. We will agree the final specification for your order. Custom versions have their own specifications and measured curves.

Applications to consider

Near-infrared illuminated inspection: Consider receiving light in 747-1200 nm while reducing shorter-wavelength background. Match the source band and detector sensitivity to the full curve.
Illumination-path development: Evaluate wavelength separation in a light source. For a reflected visible path, confirm reflection and working angle rather than inferring them from transmission.
Infrared sensing prototypes: Consider a longer-wavelength transmission window for an instrument whose detector band is covered by the measured curve. Specify any additional required wavelength coverage.

Choosing this filter

Check the full wavelength range of your light source, the wavelengths your detector responds to, and how much unwanted light you need to block. Use the full curve when choosing a filter; the product code and peak do not tell the whole story.
Tell us the angle at which light reaches the filter and whether the beam is parallel or converging. For demanding rejection or high-power use, confirm the required blocking and power-handling specifications.

Custom options

Start with this stock or sample-book design, then tell us what you need to change. We can discuss the wavelength bands, transmission, blocking, angle, glass material, size and operating conditions with you, and agree a specification for your custom filter.

Transmission spectrum

Questions about BH-A29

Where does BH-A29 transmit at least 80% in the measured curve?

The measured regions at or above 80% transmission are 747-1200 nm. They are measured intervals, not guaranteed passband tolerances. Compare the full curve with the signal wavelengths you need to retain.

Does the BH-A29 transmission curve establish heat removal?

No. The BH-A29 curve over 300-1200 nm describes transmission. For heat separation, also establish the reflected path, the source power, working angle and where the rejected light goes. Lower transmission alone does not show whether that energy is reflected or absorbed.

Discuss this filter with KUPO - include the product reference, source wavelength, working angle and required dimensions.