Each LED4D source contains four individual high-power bare LEDs. Use the configurator below to build your LED4D 4-wavelength source by choosing from the 14 available LEDs listed in the table to the right. Due to the optical configuration, certain wavelengths cannot be combined within the same source. As you select each wavelength in the configurator, unavailable wavlength pairs will be excluded from each consecutive drop down menu. Additional limitations imposed by the full configuration are outlined in the table to the right. Each combination of two wavelengths that cannot be included in the same 4-wavelength source is marked in grey, while available combinations are indicated by a green- or orange-shaded cell. The latter denotes a wavelength pair where the selection of the final two LEDs is further limited: LEDs with wavelengths below 455 nm cannot be included in an LED4D source with 660 nm, 617 nm, and 590 nm or 565 nm as the other three wavelengths. The configurator below is designed so that you cannot order a source with an unavailable wavelength configuration.
Unavailable Wavelength Combination
Available Wavelength Combination
Limited Combinations Availablea
LED4D sources with wavelength combinations of 565 nm, 617 nm, and 660 nm or 590 nm, 617 nm, and 660 nm are only available with a fourth wavelength of 455 nm or higher.
User-Configurable 4-Wavelength Source
Precisely Defined Spectral Range
Switching and Intensity Adjustments via LED Current Settings
High Emission Stability and Reproducibility
High Thermal and Mechanical Stability
No Moving Parts for Vibration-Free Operation
Long Lifetime Light Source (See the Specs Tab for Details)
Optional Adapters for Olympus, Nikon, Zeiss, and Leica Microscope Lightports
The LED4D 4-Wavelength High-Power LED Sources are ideal for applications requiring up to four wavelengths of high-performance light. These user-configurable light sources efficiently combine the output of all four LEDs into a single collimated beam. Together with a DC4100 or DC4104 4-Channel LED Driver, the LED4D provides a reliable, versatile light source with LED switching and accurate modulation of each individual LED. The source is vibration free, easy to operate, and has a long lifetime (see the Specs tab for details).
Compared to conventional, non-LED sources such as halogen and gas discharge lamps, these 4-wavelength sources offer many advantages such as higher signal-to-noise ratios (due to narrow bandwidth emission), better stability, longer life, lower replacement costs, simple operation without maintenance cycles, and no active cooling requirements or thermal filtering due to minimal thermal loads. The operating wavelength and intensity can be set quickly via the DC4100 or DC4104 driver front panel or USB connection, making this source an ideal choice for microscopy applications where multiple wavelengths are required. The source can also be modulated using the BNC input modulation connection on the DC4100 or DC4104.
The LEDs incorporated into these sources are characterized by high divergence. The light is guided through the system using mirrors, and the output is collimated with an aspheric condenser lens. This setup inherently leads to a reduction in the measured output power compared to that of the bare LEDs. Thorlabs also offers single-channel collimated LEDs, which have higher power outputs since wavelength combining optics are not needed.
The output aperture of these LED sources is internally SM2 (2.035"-40) threaded. For Olympus, Nikon, Zeiss, and Leica microscopes, optional adapters are available that directly mount the 4-Wavelength Sources onto the microscope lightport (see SM2-Threaded Microscope Adapters).
The LED4D has a flying lead terminated in a 14-pin M18 plug that is compatible with the DC4100 and DC4104 4-channel LED drivers. In the table below, LED A, LED B, LED C, and LED D denote each LED included in the source, ordered from shortest to longest wavelength.
LED A Anode
LED A Cathode
LED B Anode
LED C Anode
LED C Cathode
LED D Anode
LED A 1 Wire EEPROM I/O
Do Not Use
Do Not Use
LED B Cathode
LED D Cathode
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