Acta Optica Sinica, Volume. 45, Issue 10, 1019001(2025)

Spatial Self-Phase Modulation and Nonlinear Optical Devices Based on PDMS/WS2

Qifan Li1... Zexin Cui2, Lihua Tong1, Mengting Jiang1, Guangyuan Cui1, Churui Guo1 and Xiaodan Xu1,* |Show fewer author(s)
Author Affiliations
  • 1Hebei Key Laboratory of Microstructural Material Physics, School of Science, Yanshan University, Qinhuangdao 066004, Shandong , China
  • 2School of Physics, Beijing Institute of Technology, Beijing 100081, China
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    Objective

    We aim to overcome the stability and practicality challenges faced by traditional two-dimensional material suspensions in spatial self-phase modulation (SSPM) technology by developing a WS2 material (PDMS/WS2) based on polydimethylsiloxane (PDMS) curing, which significantly advances the device application of SSPM technology. We not only address issues such as easy precipitation, oxidation, and diffraction ring collapse caused by thermal convection effects of two-dimensional materials in suspension but also systematically explore the nonlinear optical properties of PDMS/WS2, thereby providing key parameters for the design of SSPM devices. The successful design of all-optical switches and all-optical diode devices based on PDMS/WS2 demonstrates the broad application prospects of this material in the field of nonlinear optical devices. Additionally, we have conducted a comparative analysis of solid two-dimensional material all-optical nonlinear devices based on polymethylmethacrylate (PMMA) versus those based on PDMS, which further highlights the advantages of PDMS-based solid two-dimensional materials in nonlinear optical devices. Therefore, this study is of great significance for promoting the development of nonlinear optical devices and expanding the application of two-dimensional materials.

    Methods

    20 mg of WS2 crystal powder is added to a solution containing 20 mL of isopropanol (IPA) and 10 g of PDMS-A and then sonicated for 4 h. Subsequently, 1 g of PDMS-B is introduced into the solution and magnetically stirred for 2 h. The solution is then poured into a 90 mm×15 mm petri dish and heated on a heating plate at 85 ℃ for 3 h to solidify the sample. After solidifying, the PDMS/WS2 is cut into blocks measuring 0.5 cm×1.0 cm in size and 1 mm in thickness for subsequent SSPM experiments. The SSPM experimental setup consists of the following components [Fig. 2(a)]: a Gaussian continuous-wave laser at various wavelengths; a convex lens with a focal length of 200 mm; the prepared PDMS/WS2 sample (with a thickness of 1 mm); a black screen. During the experiment, the distance between the PDMS/WS2 sample and the lens is kept constant at 100 mm, which allows the Gaussian laser beam to converge through the convex lens and illuminate the sample. Due to the optical Kerr effect, the Gaussian laser beam undergoes a phase shift as it passes through the sample, which results in mutual interference between two different light spots with the same wave vector. After the laser passes through the sample, it produces alternating bright and dark SSPM diffraction rings on the black screen.

    Results and Discussions

    1) By solidifying WS2 with PDMS, we prepare PDMS/WS2, an innovation that advances the device application of SSPM technology. Compared with traditional two-dimensional material suspensions, this solid composite material provides a new approach to the development of SSPM devices (Fig. 1). 2) Using SSPM technology, we systematically study the nonlinear optical properties of PDMS/WS2 at different wavelengths, including the nonlinear refractive index (n2) and the third-order nonlinear susceptibility (χ(3)). Experimental results show that PDMS/WS2 exhibits significant nonlinear optical effects in the wavelength range from 405 nm to 1064 nm, and these parameters exhibit regular changes with wavelength (Fig. 2 and Table 1). 3) The diffraction rings generated by PDMS/WS2 in the SSPM experiment maintain high stability without any collapse throughout, which is in stark contrast to the NMP/WS2 suspension system. Through comparative analysis, we conclude that PDMS effectively inhibits the thermal convection effect caused by laser heating, thereby ensuring the stability of the diffraction rings (Fig. 3). 4) Based on the excellent nonlinear optical properties of PDMS/WS2, we successfully design and implement all-optical switches and all-optical diode devices. These devices demonstrate strong performance in experiments, such as effective modulation of signal light by pump light and unidirectional transmission of light, which provides new ideas and platforms for the application of nonlinear optical devices (Figs. 4 and 5). 5) We compare the applications of PDMS and PMMA in solid two-dimensional material all-optical nonlinear devices. PDMS can be directly prepared through heat-induced crosslinking and exhibits excellent oxidation resistance, whereas PMMA requires coating and baking and is susceptible to oxidation degradation. PDMS also possesses good flexibility and plasticity, offering broad application prospects. In SSPM devices, PDMS is a preferred material due to its optical transparency, hydrophobicity, and long-term oxidation resistance. Especially in the aspects of device miniaturization and integration, PDMS is more effective, driving the development of devices based on PDMS/WS2.

    Conclusions

    In summary, we propose a method for preparing solid two-dimensional materials based on PDMS and explore its SSPM effect and all-optical device applications, advancing the application of SSPM technology in the field of nonlinear optical devices. We systematically investigate the nonlinear optical properties of PDMS/WS2, which demonstrate the broadband SSPM effect, nonlinear refractive index, and third-order nonlinear susceptibility. Moreover, the SSPM diffraction ring of PDMS/WS2 exhibits excellent stability without any collapse phenomenon. This feature gives PDMS/WS2 significant advantages over NMP/WS2 in SSPM experiments and applications. For practical applications, we have successfully designed all-optical switches and all-optical diodes based on PDMS/WS2, which achieve effective modulation of signal light by pump light and unidirectional transmission of light, thereby providing a new material platform for designing nonlinear optical devices and expanding the application prospects of two-dimensional materials in optoelectronic devices. In addition, we compare all-optical nonlinear devices based on solid two-dimensional materials with PMMA and PDMS substrates and find that materials based on PDMS have more advantages in nonlinear optical devices. In the future, we will continue to explore more innovative applications of PDMS-based solid two-dimensional materials, expanding their prospects in optoelectronics, optical communications, and other fields.

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    Qifan Li, Zexin Cui, Lihua Tong, Mengting Jiang, Guangyuan Cui, Churui Guo, Xiaodan Xu. Spatial Self-Phase Modulation and Nonlinear Optical Devices Based on PDMS/WS2[J]. Acta Optica Sinica, 2025, 45(10): 1019001

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    Paper Information

    Category: Nonlinear Optics

    Received: Dec. 26, 2024

    Accepted: Mar. 4, 2025

    Published Online: May. 19, 2025

    The Author Email: Xiaodan Xu (xxd@ysu.edu.cn)

    DOI:10.3788/AOS241942

    CSTR:32393.14.AOS241942

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