Fiber laser delivers 1300 and 1700 nm light simultaneously for three-photon microscopy

The first femtosecond fiber laser that economically delivers both 1300 and 1700 nm laser light simultaneously provides the repetition rate and fluence levels required for emerging three-photon microscopy applications.

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Although optical parametric amplifiers (OPAs) with a femtosecond pump laser and their tunable wavelengths are the industry standard for three-photon microscopy, as they can reach the necessary wavelengths of 1300 nm (that excite green fluorophores like green fluorescent protein or GFP) and 1700 nm (that excite red fluorophores like mRFP, mCherry, and tdTomato), they cannot emit the two wavelengths at the same time. This would only be possible with complex dual-OPA setups.

Recognizing the need for a turnkey, lower-cost solution, engineers at Cycle (Hamburg, Germany) have developed the first femtosecond fiber laser—called SOPRANO—that delivers sub-100-fs pulses at both 1300 and 1700 nm at the same time with >500 nJ (up to 900 nJ) pulse energies at 1 MHz, which is not only useful for three-photon imaging, but also adequate for two-photon and both second-harmonic- and third-harmonic-generation (SHG and THG) microscopy applications. For example, such applications would include the skin’s epidermis visualized through label-free THG microscopy.

This femtosecond life-sciences laser is about half the price of the lowest-cost OPA system and can be equipped with repetition rates up to 30 MHz needed for the aforementioned microscopy techniques, whereas OPA systems in the market typically reach only 5 MHz. Cycle leveraged its laser expertise as a spinoff company from the Ultrafast Optics and X‐rays Group at the Centre for Free‐Electron Laser Science (CFEL) at DESY in developing SOPRANO’s compact, all-fiber design. Reference:

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