Ti:sapphire, broadband vibrational sum-frequency generation spectrometer with a counter-propagating geometry

Abstract

We report the development of a counter-propagating, broadband vibrational sum-frequency generation spectrometer based on a Ti:sapphire regenerative amplifier. We present simple procedures for aligning the spectrometer and for setting the timing of the IR and visible pulses. We demonstrate that the use of this geometry offers a number of important advantages over a co-propagating geometry, including a high dynamic range, reduced nonresonant background signal at buried interfaces, and minimal beam deviation upon changing samples.

Reexamining the interpretation of vibrational sum-frequency generation spectra

“…The signal is then generated at angle  sig , which in this example is a positive angle. The angle at which the signal beam emerges is determined by the conservation of momentum equation [19] …”

Structure of Liquid Propionitrile at Interfaces. 2. Experiment

“…EXPERIMENTAL SECTION VSFG spectra were obtained using a broadband, counterpropagating VSFG spectrometer that was described in detail previously. 47 Briefly, 130 fs pulses with a center wavelength of 800 nm are generated by a Ti:sapphire amplifier (Coherent Legend Elite) at a repetition rate of 1 kHz and an average power of 3 W, and 30% of the 800 nm light seeds and pumps an infrared optical parametric amplifier (TOPAS, Light Conversion) with a difference-frequency generation module, which generates infrared (IR) pulses that are tunable between 2 and 12 μm. For the experiments described in this work, the IR wavelength was centered around 3.5 μm (2850 cm −1 ) with a full-width-at-halfmaximum bandwidth of about 100 cm −1 .…”

Interference effects in the sum frequency generation spectra of thin organic films. II: Applications to different thin-film systems

“…The counterpropagating geometry was frequently adopted 6,15,[34][35][36] in the initial development of SFG. The counterpropagating system has the advantage that the angle between the reflected SFG light and the reflected visible pump beam is greater than that for the copropagating geometry, which reduces the influence of the scattered visible light and aids more efficient collection of the SFG light.…”

“…The counterpropagating system has the advantage that the angle between the reflected SFG light and the reflected visible pump beam is greater than that for the copropagating geometry, which reduces the influence of the scattered visible light and aids more efficient collection of the SFG light. 6,15,[34][35][36] This geometry is also used in pumpprobe experiments since it can use the experimental space in an efficient way. 34 Recently, the copropagating geometry has become more widely used due to its simplicity for alignment and maintenance.…”

“…6,15,[34][35][36] This geometry is also used in pumpprobe experiments since it can use the experimental space in an efficient way. 34 Recently, the copropagating geometry has become more widely used due to its simplicity for alignment and maintenance. Since the L factors for the copropagating and counterpropagating geometries are different, it is not straight forward to make a direct comparison of the SFG spectra obtained with the different geometries.…”