We experimentally demonstrate a free-space data transmission system in an indoor simulated smoke chamber with a laser carrier of an erbium-doped actively mode-locked fiber laser and a holmium-doped actively mode-locked fiber laser. Two additional semiconductor lasers operating at 0.85 and 1.06 µm are used to calibrate the visibility of a smoke channel using the Ijaz model and compare smoke attenuation with 1.55 and 2.04 µm lasers. The eye patterns and bit error rates of 1.55 and 2.04 µm laser carriers with a data rate of 4.04 Gbps are investigated experimentally at 0.5, 0.05, and 0.005 km visibilities. The experimental results show that the smoke attenuation is wavelength dependent for V < 0.5 km. As the visibility decreases, the long wavelength laser is less affected by the attenuation and power fluctuation caused by Mie scattering. The measured optical signal-to-noise ratios of the 1.55 and 2.04 µm laser carriers for V = 0.005 km are 4.83 and 8.62 dB, respectively. The corresponding link sensitivities are −14.59 and −17.74 dBm, respectively, indicating that the 2.04 µm data transmission system is more reliable under an extremely dense smoke condition.

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Gene regulation via chemically induced dimerization (CID) is useful for biomedical research. However, the number, type, versatility, and in vivo applications of CID tools remain limited. Here, we demonstrate the development of proteolysis-targeting chimera-based scalable CID (PROTAC-CID) platforms by systematically engineering the available PROTAC systems for inducible gene regulation and gene editing. Further, we show orthogonal PROTAC-CIDs that can fine-tune gene expression at gradient levels or multiplex biological signals with different logic gating operations. Coupling the PROTAC-CID platform with genetic circuits, we achieve digitally inducible expression of DNA recombinases, base- and prime-editors for transient genome manipulation. Finally, we package a compact PROTAC-CID system into adeno-associated viral vectors for inducible and reversible gene activation in vivo. This work provides a versatile molecular toolbox that expands the scope of chemically inducible gene regulation in human cells and mice.

Nanosecond dissipative soliton resonance pulse is a demonstration of an all polarization-maintaining (PM) thulium-doped fiber laser in a nonlinear amplifying loop mirror (NALM)-based figure-eight configuration. Each loop of the apparatus includes a controllable power amplifier. With increased amplifier power, pulse width broadens linearly from 3.6 to 13.5 ns, and maximum single pulse energy can reach 27.5 nJ. Interestingly, the output peak power presents two completely opposite proportional effects in terms of the variation of settings for two amplifiers, respectively. The experimental results show that the NALM loop plays an important role for tunable pulse duration, and the unidirectional ring part makes a significant contribution for power scaling.