In this paper, we present the project and usage of multiphoton fluorescence spectroscopy sensor, based on the photonic crystal fiber as an excitation pulse transmission medium and four POF fibers acting as an emission collection elements. Usage of the photonic crystal fiber as a transmission medium allowed us to transmit the 780 nm excitation pulse with total time spread as low as 65 fs, which resulted in pulse broadening from the base 127 fs to 192 fs. Pulse was focused onto the sample via the GRIN lens, which resulted in an observable fluorescence. Collection tips of the POF fibers were additionally angled to move the collection cones towards the GRIN lens focal point, which resulted in further increase of the collection efficiency. This allowed to create a sensor capable of measuring fluorescence emission of the fluorescein solution with concentration as low as 10-4 M, with very low amount of bulk optics between the sensor and the spectrometer.
This paper presents investigation of normal and cancerous tissue by the means of one and two photon fluorescence spectroscopy. A comparison those methods has been conducted, allowing for eventual determination of granting the best possible diagnostic results.
In this paper we present the results of numerical simulations of the modal properties of the hollow core fiber with new structure of the core. We show that altering the shape of the core of the hollow core fiber allows an improvement of optical parameters, such as losses or bandwidth.
A double-clad photonic bandgap fiber (DCPBGF) can be used to transmit femtosecond signals. This fiber is supposed to be applied in endoscopy in vivo. In the environment of human body, temperature is higher than ambient temperature. For this reason one should consider influence of temperature rise on properties of ultrafast impulse propagation.
The major challenges in developing a fiber-optic nonlinear endomicroscope are efficient excitation light delivery and nonlinear optical signals collection, beam scanning, and probe miniaturization [1-4]. Therefore, double-clad PCFs (DCPCF) are used in nonlinear endomicroscope which can play a dual role of ultrashort pulse delivery and efficient collection of nonlinear optical signals . However, due to dispersion of DCPCF, dispersion compensation systems are required. In this paper the dispersion properties and losses of new design of double-clad hollow-core photonic bandgap fibers (DCPBGFs) based on a circular lattice are investigated for the first time, by using a finite difference time domain method.