Advancing multifocal nonlinear microscopy: development and application of a novel multibeam Yb:KGd(WO_4)_2 oscillator

Abstract

We present a novel Yb:KGd(WO(4))(2) oscillator design that generates six beams of temporally delayed, 253 fs, 11 nJ pulses. This allows multifocal nonlinear microscopy to be performed without the need for complicated optical multiplexers. We demonstrate our design with twelve simultaneously acquired two-photon, second-harmonic and/or third-harmonic images generated from six laterally separated foci.

Remote focusing for programmable multi-layer differential multiphoton microscopy

“…By utilizing remote focusing, we can effectively extend the imaging capability to four focal planes by coupling the output of our multi-beam Yb:KGW laser [16] to the optical system shown in Fig. 4.…”

“…4), we have implemented remote focusing on three of four excitation beams. The four beams are then angularly multiplexed to the back of the excitation objective using the optical system described by Sheetz et al [16]. This technique is commonly employed for beam combining in multi-focal microscopy [2][3][4][5][6][7][8][9][10][11][12][13][14]16].…”

“…We previously reported on an alternative method for approaching multi-focal foci generation wherein a special laser cavity is employed that outputs beams that are both temporally and spatially separated [16]. Since this cavity design delays the beams by several nanoseconds, it becomes possible to use a single-element detector, thereby taking advantage of the speed improvements of a multi-beam system without sacrificing image quality through the use of a spatially-resolved detector.…”

“…In this work we demonstrate the viability of remote focusing by using 1) a dual focus multiphoton differential laser scanning microscope, and 2) in conjunction with our novel multi-beam oscillator [16], a four beam imaging system. To our knowledge, this is the first multifocal laser scanning microscope architecture that can simultaneously image multiple axially separated focal planes that are under electronic control through remote focusing.…”

Creating multiple longitudinal foci with parametric spatio-temporal focusing

“…Multiplexing multiple foci is a challenging area of current research. Multiple transverse foci can be generated using a microarray lens 2 or by generating multiple beam positions on an output coupler in a Ti:Sapphire oscillator cavity 3 . Two longitudinal foci have been generated using a Michelson interferometer with one arm containing a deformable mirror to modify the beam divergence.…”