Optical response of fluorescent molecules studied by synthetic femtosecond laser pulses

Abstract

Abstract. The optical response of the fluorescent molecule IR144 in solution is probed by pairs of collinear pulses with intensity just above the linear dependence using two different pulse shaping methods. The first approach mimics a Michelson interferometer while the second approach, known as multiple independent comb shaping (MICS), eliminates spectral interference. The comparison of interfering and non-interfering pulses reveals that experimental information can be lost at early delay times because of linear interference between the pulses.

Solvation Stokes-Shift Dynamics Studied by Chirped Femtosecond Laser Pulses

“…This result is also in accordance to the recently observed out-of-phase behavior of fluorescence and stimulated emission when using pairs of noninterfering pulse replicas. 34 An intensity-dependent study reveals the gradual dependence of the shape of the curve from the excitation intensity, as evident from Figure 1c,d. We define the chirp effect as the normalized difference between the observed signal with chirped and TL pulses for chirp values from −10 000 fs 2 to 10 000 fs 2 .…”

Noninvasive two-photon optical biopsy of retinal fluorophores

“…In this study we used Abca4 PV/PV Rdh8 -/mice which have mutations in the ABCA4 transporter and a retinol dehydrogenase that result in elevated levels of fluorescent diretinoid-pyridiniumethanolamine (A2E) as well as Rpe65 −/− mice which carry a mutation in a critical retinoid isomerase and replicate the human form of Leber congenital amaurosis (12,13). Considering that for a given average power the TPE fluorescence rate is inversely proportional to the pulse duration and pulse repetition frequency (PRF) (14-18), we previously demonstrated over a 300% increase in fluorescence for the same average power by reducing the pulse duration from 75 to 20 fs and incorporating phase modulation of the spectral components of the excitation light to achieve high-order dispersion compensation (14,19). However, reduction of pulse duration is concomitant with an increase of spectral bandwidth.…”

Direct Observation of Coherent Oscillations in Solution due to Microheterogeneous Environment

“…The NIR dyes are also important in bio-imaging (in-vivo/in-vitro) due to low toxicity, less harmfulness and very low background signal 32 . They are mainly used as a single photon dye due to their high absorption cross-sections in the NIR region 33 . Cyanine dye is the most important NIR dye, and is readily available 31 34 .…”