3-(2-Benzimidazolyl)coumarin derivatives —highly effective laser media

Abstract

New laser dyes based on derivatives of 3-(2-benzimidazolyl)coumarin are proposed that lase under lamp and coherent (nanosecond and microsecond) pumping in the spectral range 420-700 nm and feature a high generation efficiency reaching 40% under coherent pumping (1% when lamp-pumped) and an increased operational life that surpasses that for most popular laser dyes. The nature of the substituents in the 6-and 7-positions of the coumarin ring and the ionic structure of the dyes are found to influence their spectral and lasing characteristics. Introduction.Organic dyes and related compounds that lase upon pumping by nanosecond laser pulses are currently very common. However, the number of lasing dyes is much smaller for non-monochromatic pumping by lamp pulses. This is due to photophysical and photochemical processes occurring in the cavity under the influence of the pumping radiation. Furthermore, the spectral range in which lasing occurs is overlapped unevenly by effectively lasing and photostable dyes [1]. For this reason, the search for new effectively lasing dyes with increased photochemical stability is a critical problem.The use of coumarin derivatives as lasing media in dye lasers is very interesting [2]. This is due to the fact that this class of compounds has the best energy characteristics and photostability in the blue-green spectral region [3]. The clearly pronounced polarization of their molecular structure enables the range of laser spectral tuning to be expanded using solvation effects [4][5][6][7].New compounds of this class, derivatives of 3-(2-benzimidazolyl)coumarin, were previously reported [8]. They were investigated with powerful non-coherent pumping. As a result, the studies found that the new coumarin dyes lasing upon lamp pumping in the spectral range 503-580 nm had high lasing efficiency (up to 1%) and photochemical stability (3-5 times greater than rhodamine 6G). However, the spectral-luminescent characteristics of the new compounds and the lasing parameters under coherent pumping conditions were not studied.Herein the spectral-luminescent characteristics and lasing parameters of 3-(2-benzimidazolyl)coumarin derivatives are studied under coherent pumping by radiation from an excimer XeCl-laser.Experimental Setup and Measurement Method. Figure 1 shows a diagram of the setup on which the lasing parameters of EtOH solutions of the coumarin dyes were studied. The pumping source was an electrical-discharge excimer XeCl-laser with emission energy 180-200 mJ and wavelength 308 nm. The excitation pulse duration was 60 ns. Radiation from the XeCl-laser was focused by a cylindrical lens (f = 10 cm) onto a cuvette with the dye. The dye laser cavity with base L = 15 cm was formed by a mirror (reflection coefficient R = 100%) and stack (R = 20%). The dye laser pulse energy and pumping control energy were measured using IMO-2N meters. The broad-band laser spectrum was recorded using an STE ′ -1 spectrograph. The dye laser emission was directed into the spectrograph using an optical fiber with inner dia...

Effects of Changing Substituents on the Non-Linear Optical Properties of Two Coumarin Derivatives

“…In the SM method, the atoms that form the surrounding molecules of the compounds are treated as point charges, since the interactions between molecules have a dominant electrostatic nature, taking into account long-range electrostatic effects [28,29]. Another alternative model to estimate χ (1) and χ (2) was proposed by Seidler and Champagne [30][31][32][33][34][35] with very good results.…”

“…Furthermore, coumarins display anticancer, antiviral, anti-inflammatory and anti-oxidant biological properties. Besides that, coumarin and its derivatives also work as well-known laser dyes [2][3][4] and useful probes in different photochemical and chemical studies. Most coumarins are highly fluorescent, a property that qualifies them for several applications, e.g., as high-efficiency dye-sensitized solar cells [5][6][7].…”

Design and Synthesis of Coumarin–Imidazole Hybrid Chromophores: Solvatochromism, Acidochromism and Nonlinear Optical Properties

“…Coumarin benzimidazole hybrids are highly influenced by the nature of substituent at sixth and seventh position of coumarin ring . It should be noted that protic and hydrogen‐bonding solvents, hampering the charge displacements, can also contribute to the blueshift of the absorption spectra .…”

The application of a UHPLC system to study the formation of various chemical species by compounds undergoing efficient self-aggregation and to determine the homodimerization constants (KDM) with values in the high range of 106–1010 M−1

“…They are oen used as uorescence probes, [41][42][43] chemosensors, 44 in biological and biomedical sciences, 45,46 and in dye lasers. 47 Coumarin-120 (7-amino-4-methyl-1,2-benzopyrone) (Scheme 1), abbreviated as C120, belongs to this group, having a simple NH 2 group. The uorescence quantum yields of this dye in solvents of moderate to higher polarities are very high F F $ 0.5 (ref.…”