TY - JOUR
T1 - Controlling the refractive index and third-order nonlinearity of polyimide/Ta2O5 nanolaminates for optical applications
AU - Färm, Elina
AU - Mehravar, Soroush
AU - Kieu, Khanh
AU - Peyghambarian, Nasser
AU - Ritala, Mikko
AU - Leskelä, Markku
AU - Kemell, Marianna
N1 - Funding Information:
The authors thank Lasse Karvonen and Antti Säynätjoki for sharing their insight into measuring thin films with multiphoton microscopy and for discussion on the results. The work of the Helsinki group was funded partly by the Academy of Finland (Grant No. 251142) and the Finnish Centre of Excellence in Atomic Layer Deposition. The Arizona group acknowledges support from TRIF Photonics at University of Arizona and NSF CIAN ERC.
Publisher Copyright:
© 2019 Author(s).
PY - 2019/11/1
Y1 - 2019/11/1
N2 - In this study, the authors investigated third-order optical nonlinearity in polyimide/Ta2O5 nanolaminates deposited by atomic layer deposition. Third harmonic signal measurements were done with a multiphoton microscope at an excitation wavelength of 1.55 μm, laser pulse duration of 150 fs, and estimated pulse energy of 1.2 nJ. Third-order optical nonlinearity is an essential property in optical signal applications for telecommunication. Transparency at telecommunication wavelengths and a high refractive index are desired for a material. Polyimide is optically transparent, enabling light guidance through the material. The refractive index of the material can be fine-tuned by combining polyimide with a substantially higher refractive index material - in this case, Ta2O5. The layer thicknesses in nanolaminates were varied, and the third harmonic generation was compared to plain polyimide and Ta2O5 reference films. Third harmonic generation in the nanolaminates decreased slightly and refractive index increased with increasing Ta2O5 content. Normalized third-order nonlinear susceptibilities, χ(3), calculated for the nanolaminates were between the values of Ta2O5 and polyimide and increased with increasing polyimide content.
AB - In this study, the authors investigated third-order optical nonlinearity in polyimide/Ta2O5 nanolaminates deposited by atomic layer deposition. Third harmonic signal measurements were done with a multiphoton microscope at an excitation wavelength of 1.55 μm, laser pulse duration of 150 fs, and estimated pulse energy of 1.2 nJ. Third-order optical nonlinearity is an essential property in optical signal applications for telecommunication. Transparency at telecommunication wavelengths and a high refractive index are desired for a material. Polyimide is optically transparent, enabling light guidance through the material. The refractive index of the material can be fine-tuned by combining polyimide with a substantially higher refractive index material - in this case, Ta2O5. The layer thicknesses in nanolaminates were varied, and the third harmonic generation was compared to plain polyimide and Ta2O5 reference films. Third harmonic generation in the nanolaminates decreased slightly and refractive index increased with increasing Ta2O5 content. Normalized third-order nonlinear susceptibilities, χ(3), calculated for the nanolaminates were between the values of Ta2O5 and polyimide and increased with increasing polyimide content.
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U2 - 10.1116/1.5121589
DO - 10.1116/1.5121589
M3 - Article
AN - SCOPUS:85075031105
SN - 0734-2101
VL - 37
JO - Journal of Vacuum Science and Technology A
JF - Journal of Vacuum Science and Technology A
IS - 6
M1 - 060908
ER -