SP410 Shortpass Filter (T＞85%@330-410nm,OD5@420-920nm)

Fluorescence Microscopy (Excitation Filter)

This is the most likely primary application. In a fluorescence setup, this filter serves as an Excitation Filter for blue-emitting fluorophores.

• How it works: It is placed in front of the light source to "clean up" the light. It allows the UV excitation energy to hit the sample but blocks any stray visible light from the source that would otherwise interfere with the faint fluorescence emission.

Target Fluorophores:

• DAPI: (Excitation $\approx$ 358 nm / Emission $\approx$ 461 nm)
• Hoechst 33342 / 33258: (Excitation $\approx$ 350 nm / Emission $\approx$ 461 nm)
• BFP (Blue Fluorescent Protein): (Excitation $\approx$ 380 nm)
• Calcofluor White: (Used for fungal staining).

UV Reflection Imaging / Machine Vision

In industrial inspection, this filter can be placed over a UV-sensitive camera to perform reflected UV imaging.

• Application: Detecting surface scratches, contamination, or inspecting solar cells.
• Mechanism: Because UV light scatters more easily than visible light due to its shorter wavelength, surface defects often appear much clearer in UV. The filter ensures the camera sees only the UV light and is not washed out by ambient visible light.

Request Light Source

• High-Power UV LEDs
  High-power UV LEDs emitting at 365 nm, 385 nm, 395 nm, or 405 nm represent the ideal light source for this filter. The filter efficiently passes the peak output of these LEDs while blocking the long-wavelength spectral tail that they often emit.
• Mercury Arc Lamps
  Traditional Mercury arc lamps serve as a standard light source because they generate strong, distinct spectral peaks at 365 nm (i-line) and 405 nm (h-line). The SP410 filter effectively isolates these specific ultraviolet peaks for use in excitation.
• Xenon Arc Lamps
  Xenon arc lamps provide a continuous broadband spectrum that is suitable for general UV applications. The filter carves out the necessary 330–410 nm band from this continuous source, although the total energy efficiency is lower than that of targeted LEDs.
• UV Lasers
  Specialized UV lasers operating at 355 nm, 375 nm, or 405 nm function as precise sources for advanced applications like flow cytometry or confocal microscopy. The filter acts as a cleanup optic for these sources by suppressing plasma lines and background noise.

Raman Spectroscopy (Laser Cleanup)

Raman signals are incredibly weak. If the excitation laser has any "noise" (sidebands or plasma emission lines) at longer wavelengths, that noise will bounce off the sample and completely obscure the Raman signal. The SP410 ensures the laser is purely UV before it hits the sample.

• Requirement: The Laser must be UV (e.g., 355nm or 405nm) to fit through the SP410 passband.
• Role: Removing laser noise (cleanup).
• Placement: Immediately after the laser output, before the beam splitter.