Collection: 532nm Narrow Bandpass Filter

Context: An underwater imaging system designed to detect mines or obstacles in turbid water using a 532nm green laser (which penetrates water best).

Usage of Filter: The filter is placed in front of the receiver (CCD camera or PMT) as a spectral discriminator.

Function: It acts as a solar background rejector, blocking sunlight and other ambient noise while transmitting only the specific 532nm laser return signal.

Result: This achieves a high signal-to-noise ratio, allowing the system to image faint targets underwater even during daylight hours.

Context: A high-sensitivity Raman spectroscopy system using photonic waveguides to enhance the interaction between light and the sample.

Usage of Filter: The 532nm bandpass filter is located in the excitation path between the pump laser and the waveguide input.

Function: It serves as a "laser line cleanup" filter, eliminating spectral sidebands and amplified spontaneous emission (ASE) from the laser source.

Result: This ensures that only pure 532nm light excites the sample, preventing false signals in the Raman spectrum and enabling the detection of low-concentration analytes.

Context: A high-speed fluorescence imaging system (often used in DNA sequencing or microarray analysis) that uses multiple lasers to excite different fluorophores.

Usage of Filter: The filter is used in the excitation module to spectrally condition the green laser source.

Function: It isolates the 532nm line to specifically excite Cy3 (or similar) fluorophores while rejecting any off-peak noise that could bleed into the detection channels of other fluorophores (like Cy5).

Result: This achieves precise, crosstalk-free multi-color imaging, which is critical for accurate base calling in DNA analysis.

Context: A portable Raman system capable of switching between different laser wavelengths (e.g., 532nm, 785nm, 1064nm) to optimize for different sample types (avoiding fluorescence).

Usage of Filter: The 532nm bandpass filter is mechanically or electronically selectable in the excitation optical train.

Function: It ensures that when the system switches to "532nm mode," the excitation is strictly monochromatic, removing any residual spectral output from the other laser sources or broadband noise.

Result: This allows the device to obtain clean Raman fingerprints from carbon-based materials or minerals (which respond well to 532nm) without interference from the other onboard laser sources.