Silk Nanocrack Origami for Controllable Random Lasers

Abstract

The ancient art of Origami started to evolve as a contemporary technological method for the realization of morphologically induced and unconventional advanced functional structures. Here, directional random lasers (RLs) that are formed by folding (i.e., ori) dye-doped natural protein silk fibroin (SF) film as paper (i.e., kami) are demonstrated. The folding stress induces parallel nanocracks that simultaneously function as diffuse reflectors and laser light outcouplers at the boundaries of the optical gain medium. Random lasing is observed after a threshold energy level of 0.8 nJ µm −2 with an in-plane divergence-angle of 13°. Moreover, the central laser emission wavelength is tuned from 588.7 to 602.1 nm by controlling the adjacent nanocracks distance and additional laser emission directions are introduced by further folding SF at different in-plane angles that induce rectangular and triangular geometries. More significantly, RL is fabricated via a quick, scalable, and environmentally friendly stress-induced nanocracking process maintaining its mechanical and optical properties even after 10,000 times of bending test. Hence, this study introduces a novel form of biocompatible, biodegradable, and large-area protein microlasers by using an unconventional laser fabrication approach.

Dual chaos encryption for color images enabled in a WGM–random hybrid microcavity

“…At the same time, compared with a traditional laser, a random laser also has the advantages of light emission in all directions, a simple structure and low cost; [14][15][16][17] thanks to which it is also widely used in the fields of light sources, [18][19][20] speckle-free imaging, 20,21 sensors, [22][23][24][25] information retrieval 26 and biomedicine. [27][28][29][30] Nevertheless, random lasers still face great challenges, such as a high threshold, inconvenient integration and difficulty in controlling the emission direction. 31,32 Additionally, if an unsuitable key is employed, the encryption effect for a chaotic system which adopts only a single random laser as the initial value will be severely limited, with the original image contours generally exposed after encryption.…”

Stability-Enhanced Emission Based on Biophotonic Crystals in Liquid Crystal Random Lasers

“…Furthermore, random lasers have potential applications in photonic marking, sensing and speckle-free imaging due to their broad angular emission, low spatial coherence and high-brightness [1,2]. Most importantly, as a fixed resonant cavity is not required, random lasers have the characteristics of a small size, flexible shape and low cost, which can meet the current requirements for its application as an optoelectronic device [3,4].…”

Origami nanogap electrodes for reversible nanoparticle trapping

“…This fabrication method is inspired by previous work on origami-fabrication of quasi-ordered nanocracks within protein layers, proposed as a mechanism for building distributed feedback bio-compatible lasers. 29 We apply this fabrication method to a thin layer of indium tin oxide (ITO) coated on PET (polyethylene terephthalate). This substrate is widely available and affordable because of its commercial application for liquid crystal displays and devices.…”