Optogenetics is a groundbreaking technique that provides real-time, optical control of neuronal activity. Throughout the years, it has played a vital role in dissecting brain circuitry, probing the neural basis of behavior, modeling neurological disorders, and developing next-generation therapies in neuroscience and psychiatry. 

The process requires expressing opsins, light-sensitive ion channels or pumps, in a specific neuronal population. For chronic experiments, a fiber-optic cannula is then surgically implanted above the target region to deliver a specific wavelength of light, activating or inhibiting the opsin-expressing cells. For example, blue light activates opsins like Channelrhodopsin (ChR2), while yellow or red light targets opsins such as NpHR or Jaws. For a list of available opsins, see the OSPIN APPLICATION NOTE.  

LEDs are among the most commonly used light sources in optogenetics, and are particularly suitable for experiments stimulating large regions-of-interest (with 400 µm - 1mm diameter fibers) at moderate light intensities. Their large emitter, inherent safety, reliability, and cost-effectiveness make them a preferred option across a variety of experimental designs. 

At Doric Lenses, we offer a wide range of CLED wavelengths in the near-UV (350-400 nm), visible (400-700 nm) and near IR range (700-1100 nm) for standard optogenetic applications. 

LISER™ (Laser-Induced Spontaneous Emission of Radiation) is an advanced light source providing high-intensity, broad-spectrum illumination. 

The system uses a laser pumped Ce:YAG (cerium-doped yttrium aluminum garnet) crystal, which emits a continuous spectrum from yellow to red (500–650 nm). This configuration provides exceptionally high optical power (> 85mW full spectrum in a 200 um NA 0.57 fiber) in a spectral range that is difficult to achieve with standard LEDs or laser diodes, particularly around 590 nm, optimal for activating inhibitory opsins such as NpHR and Jaws.  

In addition to its broad-spectrum output, LISER™ includes an integrated blue excitation source (laser or LED), making it a versatile, all-in-one solution capable of supporting both excitatory and inhibitory optogenetics simultaneously.  

The LISER also includes its own internal drivers, allowing independent control of two wavelength channels in the same brain region (e.g. 450 nm + 590 nm). 

Key Features: 

Note: LED drivers are only compatible with LEDs, and LD drivers only with lasers. 

Available Splitter Options: 

Doric Mini Cube (DMC)  

The DMC contains dichroic mirrors that evenly divide the intensity of light from one light source into multiple fibers (2-4 sites). Note that DMC has a built-in numerical aperture (NA) of 0.3, which limits the effective power transmission when used with patch cords of higher NA. Thus, the DMC is ideal for laser diodes, but less optimized for CLED and LISER.  

The output transmission of DMC can be 20-40% transmission, depending on the number of outputs (2-4) 

Fiber-optic Rotary Joint Splitter (FRJ)  

Fiber-optic Rotary Joint Splitter is an advanced version of DMC light splitter, which is integrated in a rotary joint for bilateral or dual-site optogenetics in freely-moving animals. It maintains comparable optical efficiency to the DMC (~40% per output channel), while enabling rotational freedom during behavior tasks. Currently, only the 1×2 configuration is offered. 
FRJ has a built-in numerical aperture (NA) of 0.22, which makes it more ideal for laser diodes, but less optimized for CLED and LISER. 

Splitter Patch Cords  

The Splitter Branching Fiber-optic Patch Cord (SBP) evenly splits the light from a large-core optic fiber into 2 or more small-core fibers. The output transmission for each branch depends on the surface area difference between the large and small cores (generally ~16% transmission*). Splitter Patch Cords are well-suited for light sources with large emitters, such as LEDs and LISER. However, when used with laser sources (which have very small emitters), the output power is much lower than with DMC or FRJ splitter.  

Doric Lenses offers several reliable and customizable light-combining solutions: 

 LISER™ Multi-Wavelength Light Source 

One of the most advanced options is the LISER™, which integrates a blue light source (either LED or laser) along with a Ce:YAG-based broadband emitter that covers the yellow to red spectrum to a single optical path. The emission can be filtered to narrow down the wavelength range (e.g., 525, 590, 612 nm), and both the blue and filtered yellow/red excitations. This all-in-one device includes its own internal drivers, allowing independent control of two wavelength channels (e.g. 450 nm + 590 nm).  

Combined LEDs  

Another compact solution is the Combined LEDs, which uses dichroic mirrors to merge up to four integrated LEDs into a single output connector. Each LED channel can be independently controlled using Doric LED drivers. 

The Combined LED box is also available with an integrated fiber-optic rotary joint (Combined LEDs with Fiber-optic Rotary Joint), ideal for multi-color stimulation in freely moving animals. Not only does this solution reduce wire tangling, but it also eliminates optical losses typically introduced by adding external rotary joints, making them particularly suitable for low-power LEDs like 595 nm. 

Doric Mini Cube (DMC) - Wavelength Division 

The DMC with wavelength division dichroic mirrors also serves as a robust and flexible light combiner. It accommodates up to four input channels of different wavelengths and works just as well to combine and/or split different wavelengths.

Maintaining optogenetics light power within the appropriate range is essential to prevent issues such as photobleaching, tissue overheating, and other unwanted side effects. However, under certain conditions, the light output from the source may exceed the optimal level for optogenetic applications—even when operating close to the threshold current setting. It is also not recommended to drive a light source close to the threshold for stability issues. In such cases, an additional component is required to deliberately reduce the light intensity. 

Doric Lenses offers different customizable light-attenuating solutions: 

U-bracket 

U-bracket is a simple optic cube which contains an inter-changeable neutral density filter to attenuate light, or a spectral filter to reduce the spectral range of a light beam. The attenuation and spectral filter can be customized by the user.  

Attenuating Mono Fiber-optic Patch Cords 

Fiber-optic patch cords with an integrated attenuating filter are ideal for applications where optical power coupled into a fiber is too high, i.e. fiber photometry excitation. Addition of attenuating filter does not affect light distribution inside the optical fiber, only transmission is reduced. Different optical fibers or attenuating factors are possible. 

Notes: