Effect of combined laser dyes on the efficiency of cholesteric liquid crystal lasers

Abstract

A high efficiency band-edge cholesteric liquid crystal (CLC) laser comprising an optimal binary-dye mixture (OBD) with 62 wt% DCM and 38 wt% PM597 as the active medium is scrutinized. The measurements indicate that both the fluorescence spectrum width and the order parameter of OBD in the host of nematic liquid crystal (BL009) enhance compared with those for each individual dye. Furthermore, at the fluorescence peak, the optical efficiency of the PM597-doped CLC laser is ~ 1.5× higher than that of DCM, and the laser emission energy for OBD-doped CLC between the wavelengths 595 nm and 613 nm is even higher than that of PM597-doped CLC, so that at the maximum fluorescence of OBD, ≈ 605 nm , the improvement is over 20%.

Programmable Rainbow-Colored Optofluidic Fiber Laser Encoded with Topologically Structured Chiral Droplets

“…Therefore, as the dopant concentration increases in the CLC droplet, the absorption of the dye molecules in CLC increases accordingly, leading to optimal performance of CLC lasers. 55 To demonstrate that absorption strength plays a dominant role in lasing wavelength shifting, here we used two dyes (B2 and NR) to explain this phenomena. As shown in Figure 3b,d, we experimentally measured the absorption and emission cross section of B2-and NR-doped CLC droplets under different chiral dopant concentrations.…”

“…The bottom panel of Figure a illustrates the pitch variation of the dye-doped liquid crystal matrix under low and high dopant concentration in CLC droplet. Therefore, as the dopant concentration increases in the CLC droplet, the absorption of the dye molecules in CLC increases accordingly, leading to optimal performance of CLC lasers …”

Electrically Tunable Two-Color Cholesteric Laser

“…By virtue of this combination, a single UV pumping beam could be used to achieve simultaneous lasing at the red and green wavelengths where the long-wavelength band edges were placed [ 1 , 25 ]. In addition, the transition dipole moments of the DCM and C540A dyes held positive-order parameters when situated within the liquid crystal (LC) hosts [ 26 , 27 ]. This indicated that the orientation of these transition dipole moments was aligned with the local molecular alignment within the LC molecules, which gave rise to greater overlap between the transition dipole moment of dye molecules and the polarization vector of the incident electromagnetic wave [ 28 ].…”

Optofluidic devices with programmable and responsive functions

“…Therefore, as dopant concentration increases in the CLC droplet, the absorption of the dye molecules in CLC increases accordingly, leading to optimal performance of CLC lasers. 184 To demonstrate that absorption strength plays a dominant role in lasing wavelength shifting, here four distinct dyes (B2, NR, C6, and DCM) were used to explain this phenomenon. As shown in Figure 4.20 (a-d), the absorption and emission cross-section of B2-, NR-, C6-, and DCM-doped CLC droplets were experimentally measured under different chiral dopant concentrations.…”