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Electronic control of coherence in a two-dimensional array of photonic crystal surface emitting lasers.

Taylor RJ, Childs DT, Ivanov P, Stevens BJ, Babazadeh N, Crombie AJ, Ternent G, Thoms S, Zhou H, Hogg RA - Sci Rep (2015)

Bottom Line: We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements.This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers.Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young's Slits experiment.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom.

ABSTRACT
We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements. This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers. Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young's Slits experiment. In addition to allowing the all-electronic control of the interference pattern, this type of device offers new routes to power and brightness scaling in semiconductor lasers, and opportunities for all-electronic beam steering.

No MeSH data available.


Schematic of the four element PCSEL array.The cut-away is to the level of the first epitaxial step, and shows the position of the photonic crystal lattice which constitutes the PCSEL. Vertical emission from three devices is shown, with lateral coupling via the coupler sections. Two-dimensional coupling of PCSEL elements is achieved through orthogonal scattering at a neighbouring PCSEL.
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f1: Schematic of the four element PCSEL array.The cut-away is to the level of the first epitaxial step, and shows the position of the photonic crystal lattice which constitutes the PCSEL. Vertical emission from three devices is shown, with lateral coupling via the coupler sections. Two-dimensional coupling of PCSEL elements is achieved through orthogonal scattering at a neighbouring PCSEL.

Mentions: The PCSEL array described here differs from the GSE array in that the light scattering element now incorporates the gain element. Figure 1 shows a schematic of our device. Here, the PCSEL elements are optically coupled through connecting contacted waveguide regions. This contrasts the GSE that has vertically scattering gratings connecting single-mode wave-guided gain elements. The necessity for single-mode waveguide gain elements in the GSE designs will ultimately limit gain volume and therefore output power. In the device presented here, we are able to harness many of the beneficial properties of PCSELs1234567, in addition to the fabrication technology to achieve optical coupling within the 2D array now being comparatively simple to implement. Furthermore, phase matching conditions between the PCSEL elements may be easily achieved for all elements of the array by designing the coupling waveguides to be of a suitable length. By using such large PCSEL element separation (large as compared to the substrate thickness), thermal isolation of individual elements is achieved. As a consequence, kilowatt class coherent semiconductor laser arrays should be possible utilising PCSEL technology with the added advantage that they emit a coherent beam that can be focused down to the diffraction limit. This significant difference offers the prospect of an increase in brightness by several orders of magnitude over the state-of-the-art. We demonstrate the formation of electronically controlled coherent 2D arrays here through the demonstration of a 2D Young’s Slits experiment.


Electronic control of coherence in a two-dimensional array of photonic crystal surface emitting lasers.

Taylor RJ, Childs DT, Ivanov P, Stevens BJ, Babazadeh N, Crombie AJ, Ternent G, Thoms S, Zhou H, Hogg RA - Sci Rep (2015)

Schematic of the four element PCSEL array.The cut-away is to the level of the first epitaxial step, and shows the position of the photonic crystal lattice which constitutes the PCSEL. Vertical emission from three devices is shown, with lateral coupling via the coupler sections. Two-dimensional coupling of PCSEL elements is achieved through orthogonal scattering at a neighbouring PCSEL.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542471&req=5

f1: Schematic of the four element PCSEL array.The cut-away is to the level of the first epitaxial step, and shows the position of the photonic crystal lattice which constitutes the PCSEL. Vertical emission from three devices is shown, with lateral coupling via the coupler sections. Two-dimensional coupling of PCSEL elements is achieved through orthogonal scattering at a neighbouring PCSEL.
Mentions: The PCSEL array described here differs from the GSE array in that the light scattering element now incorporates the gain element. Figure 1 shows a schematic of our device. Here, the PCSEL elements are optically coupled through connecting contacted waveguide regions. This contrasts the GSE that has vertically scattering gratings connecting single-mode wave-guided gain elements. The necessity for single-mode waveguide gain elements in the GSE designs will ultimately limit gain volume and therefore output power. In the device presented here, we are able to harness many of the beneficial properties of PCSELs1234567, in addition to the fabrication technology to achieve optical coupling within the 2D array now being comparatively simple to implement. Furthermore, phase matching conditions between the PCSEL elements may be easily achieved for all elements of the array by designing the coupling waveguides to be of a suitable length. By using such large PCSEL element separation (large as compared to the substrate thickness), thermal isolation of individual elements is achieved. As a consequence, kilowatt class coherent semiconductor laser arrays should be possible utilising PCSEL technology with the added advantage that they emit a coherent beam that can be focused down to the diffraction limit. This significant difference offers the prospect of an increase in brightness by several orders of magnitude over the state-of-the-art. We demonstrate the formation of electronically controlled coherent 2D arrays here through the demonstration of a 2D Young’s Slits experiment.

Bottom Line: We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements.This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers.Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young's Slits experiment.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic &Electrical Engineering, Centre for Nanoscience &Technology, North Campus, The University of Sheffield, Broad Lane, Sheffield, S3 7HQ, United Kingdom.

ABSTRACT
We demonstrate a semiconductor PCSEL array that uniquely combines an in-plane waveguide structure with nano-scale patterned PCSEL elements. This novel geometry allows two-dimensional electronically controllable coherent coupling of remote vertically emitting lasers. Mutual coherence of the PCSEL elements is verified through the demonstration of a two-dimensional Young's Slits experiment. In addition to allowing the all-electronic control of the interference pattern, this type of device offers new routes to power and brightness scaling in semiconductor lasers, and opportunities for all-electronic beam steering.

No MeSH data available.