Features

• Ultra-High Peak Power (>500 kW) for Deep Imaging
• >100 nm Wide Spectrum Allows Multiple Fluophores to be Excited Simultaneously
• 10 Femtosecond Pulse Provides More Signal and Less Photodamage
• Small Footprint Conserves Lab Bench Space

More Signal, Less Photodamage
In two-photon microscopy, the fluorescence signal intensity depends quadratically on both the excitation laser intensity and average power divided by repetition rate and laser pulse width:

Here, P_ave is the average power of the femtosecond laser, f_rep is the repetition rate, and is the pulse length.

The two-photon signal can be increased either by increasing the average power of the femtosecond laser or by reducing the pulse width. Increasing the average power requires a high-power pump laser, which is expensive to buy and exhibits a high cost of ownership.

The Octavius-2P offers a cost-effective alternative. Instead of incorporating a multi-watt average output power system, we reduced the pulse width to 10 fs, thereby increasing the intensity tenfold compared to 100 fs systems with the same average power. The result is better signal intensity with reduced average laser power, which decreases the probability of photodamage.

The Octavius-2P is pumped using newly developed Optically Pumped Semiconductor Laser (OPSL) technology. These next-generation pump sources allow for high compactness and low cost of ownership. The ultra-high peak power of over 500 kW, compared to other commercially available 300 kW lasers, provides the ability to probe deeper into biological tissue. Additionally, the extended spectral bandwidth of the 10 fs laser pulse stretches over 100 nm, allowing the Octavius-2P laser to efficiently excite multiple fluorophores simultaneously.

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Mouse Intestine

The images are taken with a two-photon microscope using the Octavius-2P as the laser source. The sample was labeled with Alexa 350 and Alexa 568 dyes, which have fairly well separated excitation bands. Exciting these two dyes simultaneously with a traditional 100 fs laser source is difficult, since the bandwith of the source is too narrow. The 10 fs Octavius-2P is able to excite both fluorophores due to its larger spectra bandwith of over 100 nm.

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Dispersion Compensating Mirrors

A pair of Dispersion-Compensating Mirrors, DCMP175, is available to correct the dispersion occurs during the ultrashort pulses travel through an optical system.

Since femtosecond pulses are comprised from many different wavelengths, pulse broadening, as a result of dispersion, will occur when the laser light passes through a dielectric medium (e.g., glass). This pulse broadening is attributed to the nonlinear wavelength dependence of the refractive index of the optical components through which the light travels. Shorter wavelengths are associated with higher indices of refraction than longer wavelengths causing them to travel slower than longer wavelengths.

The pulse dispersion caused by the wavelength-dependent nature of the refractive index can be corrected using Thorlabs' dispersion-compensating mirror set. These mirrors are specifically designed so that longer wavelengths experience larger group velocity delay than shorter wavelengths, thereby negating the pulse broadening caused by the optical elements within the imaging system.

Custom bandwidth configuration is available. Please Contact Thorlabs for details.