Mainz 2026 – wissenschaftliches Programm

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K: Fachverband Kurzzeit- und angewandte Laserphysik

K 5: Optical Methods

K 5.2: Vortrag

Donnerstag, 5. März 2026, 11:30–11:45, HS 20

Nonlinear absorption and lasing properties of Rhodamine-110 dye using a 532 nanosecond laser — •Abeer Salah, Elham M. Mostafa, Randa Saad Hassan, and Ahmed M. Saad for the Z Scan Abeer Salah collaboration — Department of laser sciences and interactions LSI, National Institute of Laser Enhanced Sciences (NILES), Cairo University, Giza 12613, Egypt

Rhodamine 110 (Rh-110) is a xanthene-based fluorescent dye that has garnered significant attention in scientific and industrial communities. The linear and nonlinear optical properties of the laser dye Rhodamine 110 in an ethanol solvent at various concentrations, ranging from 0.001 mM to 3 mM, were studied. the absorption and emission wavelengths were found to be 501 nm and 522 nm, respectively. The oscillator strength, f = 0.0846 ± 0.008, and transition dipole moment, µ ≈ 3.0 ± 0.15 D, are reported. Nonlinear absorption was carried out via a Z-scan using 532 nm nanosecond pulses. The measurements reveal saturable absorption, which explains the lasing behavior of the Rh-100 series and negative nonlinear absorption coefficients. The lasing characteristics were evaluated using second-harmonic generation of a Q-switched Nd:YAG laser at 532 nm, with varying Rh110 concentrations in an ethanol solvent. Amplified Spontaneous emission (ASE) was noted among concentrations from 0.9 mM to 3 mM. The threshold energies were determined to be between 1-4.5mJ, depending on the concentration, with the optimum condition for ASE being a narrowing FWHM (3 nm) among concentrations of 1.2 to 3 mM. Additionally, fluorescence decay lifetimes were measured using a picosecond pulsed N2 laser, revealing a mono-exponential decay time τ from 8 to 16 ns depending on concentration. The RH110 can be utilized in laser and photonic devices due to its nonlinear optical properties.

Keywords: Lasing threshold; Z scan; lifetime; Saturable absorption