A novel, highly uniform parallel two-photon lithography method, based on a digital micromirror device (DMD) and a microlens array (MLA), is presented in this paper. This method enables the generation of thousands of individual femtosecond (fs) laser foci with on-off switching and variable intensity. For parallel fabrication in the experiments, a 1600-laser focus array was created. The focus array's intensity uniformity demonstrated a remarkable 977% figure, and the intensity-tuning precision for each focus reached 083%. A uniform grid of dots was fabricated to showcase the concurrent production of sub-diffraction-limited features. These features are below 1/4 wavelength in size or 200nm. The potential of multi-focus lithography lies in its ability to expedite the creation of massive 3D structures that are arbitrarily intricate, featuring sub-diffraction scales, and operating at a fabrication rate three orders of magnitude faster than current methods.

Diverse applications of low-dose imaging techniques span a broad spectrum, encompassing everything from biological engineering to materials science. Phototoxicity and radiation-induced damage to samples can be mitigated by utilizing low-dose illumination. Poisson noise and additive Gaussian noise, unfortunately, become significant contributors to the degradation of image quality, particularly in low-dose imaging scenarios, affecting key aspects such as signal-to-noise ratio, contrast, and resolution. Our work demonstrates a low-dose imaging denoising methodology that utilizes a noise statistical model, embedded within a deep neural network. To avoid relying on clear target labels, a pair of noisy images are leveraged; the network's parameters are adjusted via the statistical characteristics of the noise. Simulated data from optical and scanning transmission electron microscopes, under varying low-dose illumination conditions, allow for the evaluation of the suggested method. We developed an optical microscope that enables the capture of two noisy measurements of the same information in a dynamic process, characterized by each image containing independent and identically distributed noise. A low-dose imaging technique, using a biological dynamic process, is employed and subsequently reconstructed via the proposed method. The proposed method was experimentally assessed on optical, fluorescence, and scanning transmission electron microscopes, yielding improved signal-to-noise ratios and spatial resolution in the resultant images. We posit that the proposed methodology is applicable across a broad spectrum of low-dose imaging systems, encompassing both biological and materials science domains.

Quantum metrology provides a vast improvement in measurement precision, going far beyond the theoretical limits of classical physics. A photonic frequency inclinometer, based on a Hong-Ou-Mandel sensor, is showcased for exceptionally precise tilt angle measurements across a wide range of tasks, encompassing mechanical tilt determination, the monitoring of rotational/tilt dynamics in light-sensitive biological and chemical entities, and advancing the efficacy of optical gyroscopes. The theory of estimation reveals that a broader single-photon frequency range and a greater frequency disparity in color-entangled states can both enhance the achievable resolution and sensitivity. Fisher information analysis empowers the photonic frequency inclinometer to dynamically determine the best sensing location despite experimental shortcomings.

Fabrication of the S-band polymer-based waveguide amplifier has been accomplished, but optimizing its gain performance is a considerable difficulty. The technique of energy transfer between different ionic species proved effective in boosting the efficiency of Tm$^3+$ 3F$_3$ $ ightarrow$ 3H$_4$ and 3H$_5$ $ ightarrow$ 3F$_4$ transitions, which, in turn, enhanced emission at 1480 nm and boosted gain in the S-band. Introducing NaYF4Tm,Yb,Ce@NaYF4 nanoparticles into the core layer of the polymer-based waveguide amplifier facilitated a maximum gain of 127dB at a wavelength of 1480nm, showcasing a 6dB enhancement relative to previous work. Lificiguat purchase The gain enhancement technique, as indicated by our results, effectively improved S-band gain performance, offering beneficial guidance for gain optimization across various other communication bands.

Inverse design, though useful for producing ultra-compact photonic devices, encounters limitations stemming from the high computational power needed for the optimization processes. General Stoke's theorem asserts that the aggregate change along the outer boundary is equivalent to the cumulative change integrated across the interior sections, allowing for the division of a sophisticated system into simpler, manageable modules. Consequently, we incorporate this theorem into inverse designs to create a novel methodology for optical device design. Compared to traditional inverse design methods, the localized regional optimizations yield a significant reduction in computational load. A five-fold reduction in computational time is observed when compared to optimizing the whole device region. The proposed methodology's performance is verified experimentally by designing and fabricating a monolithically integrated polarization rotator and splitter. Polarization rotation (TE00 to TE00 and TM00 modes) and power splitting, with the precise power ratio, are accomplished by the device. The demonstrated average insertion loss is measured to be below 1 dB, along with crosstalk levels that remain below -95 dB. The new design methodology's advantages and feasibility for achieving multiple functions on a single monolithic device are confirmed by these findings.

An optical carrier microwave interferometry (OCMI)-based three-arm Mach-Zehnder interferometer (MZI) is introduced and used to experimentally interrogate a fiber Bragg grating (FBG) sensor. By combining the interferogram produced by the interference of the three-arm MZI's middle arm with both the sensing and reference arms, and superimposing the results, a Vernier effect is achieved, thus increasing the system's sensitivity in our sensing scheme. A solution to the cross-sensitivity issues, specifically those affecting sensing fiber Bragg gratings (FBGs), is provided by the simultaneous interrogation of the sensing and reference FBGs using the OCMI-based three-arm-MZI. Conventional sensors utilizing optical cascading, to produce the Vernier effect, are susceptible to temperature and strain. The OCMI-three-arm-MZI based FBG sensor, when put to the test in strain-sensing experiments, exhibited a sensitivity 175 times higher compared to the two-arm interferometer FBG sensor. A substantial improvement in temperature stability has been achieved, lowering the temperature sensitivity from 371858 kHz/°C to 1455 kHz/°C. The sensor's considerable strengths, including its high resolution, high sensitivity, and low cross-sensitivity, significantly enhance its suitability for precise health monitoring in extreme environments.

Our analysis focuses on the guided modes in coupled waveguides, which are made of negative-index materials and lack both gain and loss. The existence of guided modes within the structure is shown to be influenced by the interplay between non-Hermitian phenomena and geometric parameters. The disparity between the non-Hermitian effect and parity-time (P T) symmetry is notable, and a straightforward coupled-mode theory featuring anti-P T symmetry can elucidate this difference. A review of the implications of exceptional points and slow-light effects is offered. Within the context of non-Hermitian optics, this study underscores the promise of loss-free negative-index materials.

Aiming at high-energy few-cycle pulses surpassing 4 meters, we report on the dispersion management strategies employed in mid-IR optical parametric chirped pulse amplifiers (OPCPA). The scope of feasible higher-order phase control is circumscribed by the pulse shapers operative within this spectral region. To produce high-energy pulses at 12 meters, utilizing DFG driven by signal and idler pulses from a midwave-IR OPCPA, we present alternative mid-IR pulse-shaping methods, specifically a germanium prism pair and a sapphire prism Martinez compressor. Rescue medication Finally, we explore the limitations of bulk compression using silicon and germanium, specifically considering the impact of multi-millijoule pulses.

We introduce a super-resolution imaging approach that is focused on the fovea, achieving improved local resolution via a super-oscillation optical field. The foveated modulation device's post-diffraction integral equation is established. Subsequently, the objective function and constraints are set. Finally, an optimized solution for the amplitude modulation device's structural parameters is achieved using a genetic algorithm. The data, once resolved, were subsequently inputted into the software to perform an analysis of the point diffusion function. An analysis of different ring band amplitude types' super-resolution performance indicated that the 8-ring 0-1 amplitude type achieved the optimal results. The experimental apparatus, built according to the simulation's specifications, loads the super-oscillatory device's parameters onto the amplitude-type spatial light modulator. The resultant super-oscillation foveated local super-resolution imaging system delivers high image contrast throughout the entire viewing field and enhances resolution specifically in the focused portion. Lipopolysaccharide biosynthesis Subsequently, this approach yields a 125-times super-resolution magnification effect within the foveated viewing region, ensuring the super-resolution imaging of the local field while maintaining the resolution of other regions. Our system's ability to achieve its goals and its effectiveness is demonstrated by the experimental results.

Experimental results highlight a 3-dB coupler with polarization/mode insensitivity for four modes, utilizing the concept of an adiabatic coupler. In the proposed design, the first two transverse electric (TE) modes and the first two transverse magnetic (TM) modes are supported. Within the 70nm optical range (from 1500nm to 1570nm), the coupler's performance is demonstrated by a maximum insertion loss of 0.7dB, a crosstalk maximum of -157dB and a maximum power imbalance of 0.9dB.