Optical Beam Combining System Lambda 421

A brand-new, patented idea for combining various light sources with various spectra into a single common output beam is called the Lambda 421 beam combiner. Before passing through a bandpass filter and onto the optical path, each individual light source is collimated. Each light source's filters serve as mirrors that reflect the collimated beams from the preceding sources of light. The optical routes for each point, including the reflections that take place, are shown in the picture below:

Optical path for each point of the light sources, from 0 to 3. Based on the total number of reflections, the light sources' positions are given numbers.

Originally, a dichroic ladder was used to combine more than two light sources. If the wavelengths of the various light sources do not overlap, dichroic mirrors, which change from transmission to reflection at a certain point in the spectrum, enable the merging of different light sources. This method's drawback is that light sources are difficult to switch.

In order to prevent the light from being obstructed by the next dichroic in line, dichroic ladders also necessitate particular attention to the order in which the light sources are introduced into the optical path. To choose the desired range of wavelengths for each light source, additional bandpass filters must often be placed before the dichroic. The ladder's overall light output diminishes with each filter and dichroic employed in it.

FEATURES

• Adaptable 4-channel ultra-high-speed LED light source
• Simple spectrum flexibility is made possible by a novel optical architecture
• A wide range of LEDs between 340 and 900 nm are readily available

COMMON APPLICATIONS

• Fluorescent microscopy
• Calcium imaging
• FURA
• Optogenetics
• High speed wavelength selection

The Lambda 421 was built with a compact beam combiner and an efficient, condensed optical path in mind. The STR from Semrock and other thin-film bandpass filters reflect more than 90% of out-of-band light. It is possible to employ the filters for both light attenuation and reflection from the other sources if the band passes of the individual light sources do not overlap. Sutter was able to combine four light sources in a small design with fewer losses than was previously possible by organizing the filters and sources into a pentagon. Also, since no other input reflects from the last place in the optical train, there is no need for a filter there. As long as you are aware of the potential losses if there are filters in use that overlap this light source, you can utilize this input with any type of light source. The output for the combined sources is the fifth side of the pentagon. The filters are mounted on little sliders inside the pentagon's core and are easily exchangeable. Around the pentagon, light sources and related filters can be organized in any configuration.

Notes:

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• Without being reflected, light from location #0 travels straight to the device output. The source with the highest desired output may choose to be in this position.
• If a broad-band source were preferred, the filter for the fourth light source might be removed because it is not employed as a reflective surface.
• To provide the highest light output in setups with less than four light sources, sources should be filled from the lowest to the highest number of reflections.
• Each input's optical path is angled at an angle of 18 degrees with respect to the port's filter. The band pass will somewhat shift in favor of shorter wavelengths as a result. While a coating tailored for this purpose would be preferable, stock -STR filters can be utilized if the band pass shift is taken into account while choosing the filters. This makes it possible to combine lasers and narrow-band sources like LEDs with broad-band sources like arc lamps or white light LEDs.
• LEDs allow for the shuttering of wavelengths at the rate of the individual source. The Lambda 421 is one of, if not the fastest wavelength switcher on the market, switching in 10 to 25 microseconds for Sutter Instrument HPX and TLED products. The Lambda optical beam combiner is made to be adaptable and scalable. A straightforward setup modification and even some extra filters can result in a completely different output if your illumination requirements alter over time.

Lambda 421 - LED Spectra Options.