Laser Guided Assembly of 2-D materials
PM Assembly using Optical Trapping. Optical trapping has been used to assemble microscopic particles (e.g. 1 mm diameter microspheres) in 1D, 2D, or 3D arrays, but not nanoparticles (NPs) generally. A 1D array can be created using a SWOT; the antinodes in a standing wave generated by two counter-propagating Gaussian beams trap particles in an array. Arrays of traps using holographic optical tweezers (HOT) using diffractive element partitions a single collimated laser beam into several beams-each of which can be focused into the back aperture of an objective lens with a slightly different incident angle, and then focused to create an array of traps. Recently, a computer-controlled, liquid crystal spatial light modulator (SLM) was used to create HOTs that can be dynamically reconfigured into a variety of patterns. As a fix, an SLM can be implemented using wave-front modulation methods, such as polarization multiplexing and division of an SLM face. Other practical problems for using HOTs for trapping are the limited number of pixels, the optical damage threshold, and the sluggish refresh rate. A nematic liquid-crystal SLM, one of the most widely used types, typically exhibits a low damage threshold (< 100 W/cm2), a zero-order diffraction efficiency of only 61 %, an rms wavefront distortion of l/5 (@785 nm) and a slow switching rate (58 Hz @ 785 nm).
Paul A, Timp G, “How to Manufacture Photonic Metamaterials”, Advanced Materials Technologies, 2025, doi: 10.1002/admt.202500313 Link to publication.
Paul A, Volk A, Hokmabadi M, Rigo E, Kermani H, Almonte-Garcia L, Finamore T, Iwamoto K, Roeder R, Timp G, “Modular Assembly of Metamaterials Using Light Gradients”, Advanced Materials 2024, doi.org/10.1002/adma.202401344 Link to publication.
Perry N, Kennedy EM, Timp G, “Wiring Together Synthetic Bacterial Consortia to Create a Biological Integrated Circuit”, ACS Synthetic Biology 2016, doi:10.1021/acssynbio.6b00002 Link to publication.
Mirsaidov U, Timp W, Timp K, Mir M, Matsudaira P, Timp G, “An Optimal Optical Trap for Bacterial Viability”, Phys. Rev. E, 2008, 78, 2, 021910. doi: 10.1103/ PhysRevE.78.021910. Link to publication.
Mirsaidov U, Scrimgeour J, Timp W, Timp K, Mir M, Matsudaira P, Timp G, “Live Cell Lithography: Using Optical Tweezers to Create Synthetic Tissue”, Lab on a Chip, 2008. doi: 10.1039/B807987K. Link to publication.
Akselrod GM, Timp W, Mirsaidov U, Zhao Q, Li C, Timp R, Timp K, Matsudaira P, Timp G, “Laser-Guided Assembly of Heterotypic 3D Living Cell Microarrays”, Biophys. J. 2006 91 (9): 3465-3473. doi: 10.1529/biophysj.106.084079. Link to public