Influence of index contrast in two dimensional photonic crystal lasers

Jørgensen, Mogens B.; Petersen, Sten; Christiansen, Mads Brøkner; Buss, Thomas; Smith, C. L.

doi:10.1063/1.3443718

Cited by 12 publications

(9 citation statements)

References 18 publications

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“…3(a)) show two narrow peaks (linewidths ~0.5 nm), located at wavelengths of 560.5 and 563.1 nm (for device I) and at 575.7 and 577.2 nm (for device II). The separation between the two peaks is consistent with the two expected peaks at each side of the band gap [14,15,18]. The different emission wavelengths of devices I are II are a consequence of their different film thickness.…”

Section: D Dfb Lasers With Pdi-o/mr-i7030r and Rh6g/su8 Active Filmssupporting

confidence: 70%

“…A variation of T-NIL, which combines thermal and UV-curing to imprint a resist at a moderate low temperature, is the so-called combined nanoimprint and photolithography (CNP). CNP has been used to obtain 2D DFB lasers using pyrromethane as laser dye dispersed in UVcurable resists, such as Ormocore or SU-8 [14,15]. A drawback of CNP is that fewer resists are available, which constitutes a limitation to optimize properties such as the photostability.…”

Section: Introductionmentioning

confidence: 99%

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Two-dimensional distributed feedback lasers with thermally-nanoimprinted perylenediimide-containing films

Calzado¹,

Retolaza²,

Merino³

et al. 2017

Opt. Mater. Express

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Two-dimensional (2D) distributed feedback (DFB) lasers with gratings imprinted by thermal nanoimprint lithography on the active film are reported. They show thresholds for lasing of ∼10 kW/cm 2 , similar to the most efficient imprinted DFB lasers reported; and long operational lifetimes (under ambient conditions) of ∼12 × 10 4 pump pulses. The key for their successful operation has been the selection of a highly efficient and stable dye, perylene orange (PDI-O), and a proper matrix to host it, the fluoro-modified thermoplastic resist mr-I7030R, which has enabled 2D imprinting while preserving the dye optical properties. The use of the UV-curable resist SU8 as an alternative matrix for PDI-O to be imprinted by combined nanoimprint and photolithography was also investigated, and was concluded to be unsuccessful due to severe photoluminescence quenching. By replacing PDI-O with Rhodamine 6G, lasers with reasonable thresholds, but with significantly inferior operational lifetimes in comparison to PDI-O/mr-I7030R devices, were obtained. Casado, H. Tsuji, E. Nakamura, and M. A. Díaz-García, "Carbon-bridged oligo(p-phenylenevinylene)s for photostable and broadly tunable, solution-processable thin film organic lasers," Nat. Commun. 6, 8458 (2015).

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Section: D Dfb Lasers With Pdi-o/mr-i7030r and Rh6g/su8 Active Filmssupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Two-dimensional distributed feedback lasers with thermally-nanoimprinted perylenediimide-containing films

Calzado¹,

Retolaza²,

Merino³

et al. 2017

Opt. Mater. Express

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“…It is well known that in DFB lasers with index modulation, the increase of index contrast (IC)-defined as (n eff high /n eff low ), where n eff high is the effective index of a waveguide of thickness h þ d and n eff low the one of a waveguide of thickness h-leads to higher coupling constants that would increase the gain. 16,21 However, an increase of IC would also increase the waveguide propagation losses. This latter effect might be significant in very thin films with poor mode confinement, or in devices in which DFB emission appears at higher order modes, for which the maximum of the intensity mode profile is at the interface, where the grating is located.…”

Section: -mentioning

confidence: 99%

Influence of the excitation area on the thresholds of organic second-order distributed feedback lasers

Calzado

Villalvilla

Boj

et al. 2012

Applied Physics Letters

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It is shown that the optical pump power (or energy) density thresholds required to obtain lasing from organic second-order distributed feedback lasers, increase when the excitation area (A) is smaller than a certain value (A crit ). So, in order to obtain the minimum possible thresholds and to ensure that they constitute adequate quantities for comparison purposes, the condition A > A crit should be fulfilled. Results also indicate that when A < A crit (A crit $ 0.1 mm 2 for the devices studied here), the operational device lifetime, which depends mainly on the pump power (or energy) density, becomes drastically reduced. 1,2 The interest in OSLs increased with the discovery of stimulated emission in optically pumped semiconducting polymer films, 3,4 since they opened the possibility of using electrical excitation. The goal of obtaining laser diodes was initially the main motivation to decrease the laser thresholds of OSLs, so many works focused in improving the active materials and the resonators. Although diode lasers have not been demonstrated yet, thanks to all these efforts, laser thresholds have been decreased so much that today it is possible to pump with cheap inorganic diode lasers 1,5 and even with light emitting diodes.6 Therefore, these low-cost and compact optically pumped lasers are by themselves useful for applications. 1,2Among the various types of OSLs reported in the literature, distributed feedback (DFB) lasers have been particularly successful.1,2 So today they are being used to develop applications in the fields of telecommunications, 2 biosensing, and chemical sensing. 7,8 In DFB lasers, the active material is deposited as a thin film over an appropriate substrate so it constitutes a waveguide. Feedback is achieved by the incorporation of periodic nanostructures (obtained by modulating either the refractive index or the gain) that Bragg-scatter the light, thus, avoiding the need of good-quality end facets. In a one-dimensional (1D) DFB laser, the wavelength that satisfies the Bragg condition (k Bragg ) given bywhere m is the order of diffraction, n eff is the effective refractive index of the waveguide, and K is the grating period, constitutes the resonant wavelength in the cavity, which will then be diffracted in the grating in different directions.For second-order DFBs (m ¼ 2 in Eq. (1)), light is coupled out of the film in a direction perpendicular to the waveguide film, by first-order diffraction. DFB resonators can be easily integrated into planar organic waveguides, which is a clear advantage from the fabrication point of view, as compared to other types of laser cavities. In general, OSLs demand very intense pumping conditions due to the short photoluminescence (PL) lifetimes of the active materials (typically 1 ns in the case of fluorescent materials). So, excitation is performed by tightly focusing the pump beam through the gain medium provided by a pulsed laser source. Many of the milestones in achieving low thresholds (expressed as energy per pulse) reported in the literature have...

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“…As presented in different publications (e.g., [4][5][6]), hybrid polymers can be successfully patterned using nanoimprint lithography. While these works show that requirements regarding aspect ratio, dimension and surface quality of imprinted structures can be successfully fulfilled using already approved techniques combined with hybrid polymers, the limitation of the imprint area is not solved, yet.…”

Section: Introductionmentioning

confidence: 99%

Hybrid polymers processed by substrate conformal imprint lithography for the fabrication of planar Bragg gratings

et al. 2016

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Within this work, we present an approach to use UV-enhanced substrate conformal imprint lithography (UV-SCIL) as a soft imprint technique combined with excimer laser irradiation to manufacture Bragg gratings within planar waveguides on a full wafer scale. For the first time, different hybrid polymers (OrmoComp®, OrmoStamp, OrmoCore, OrmoClad and OrmoClear) could be successfully patterned using UV-SCIL. For OrmoComp® (showing results very similar to OrmoStamp and OrmoClad) a complete imprint process could be realized. OrmoCore formed an inhibition layer in the presence of oxygen during the imprint, as could be observed for the use of OrmoClear as well. Processing options were elaborated to reduce the inhibition effect significantly, whereby the latter is mainly due to the atmospheric oxygen containing PDMS layer of the UV-SCIL working stamp. Further on, the successful realization of a planar Bragg grating operating at the telecom wavelength is demonstrated by tuning the refractive index (RI) of OrmoComp® using a phase mask and an UV excimer laser. FTIR-measurements show that the change in refractive index can be clearly correlated with a change in the chemical composition of the hybrid polymer during laser exposure

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Influence of index contrast in two dimensional photonic crystal lasers

Cited by 12 publications

References 18 publications

Two-dimensional distributed feedback lasers with thermally-nanoimprinted perylenediimide-containing films

Two-dimensional distributed feedback lasers with thermally-nanoimprinted perylenediimide-containing films

Influence of the excitation area on the thresholds of organic second-order distributed feedback lasers

Hybrid polymers processed by substrate conformal imprint lithography for the fabrication of planar Bragg gratings

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