A projection objective includes at least four curved mirrors, which include a first curved mirror that is a most optically forward mirror and a second curved mirror that is a second most optically forward mirror, as defined along a light path. In addition, an intermediate lens element is disposed physically between the first and second mirrors, the intermediate lens element being a single pass type lens. The objective forms an image with a numerical aperture of at least substantially 1.0 in immersion.

The present disclosure relates to a coaxial four-reflection optical system with visible light long-wave infrared common-aperture imaging, and belongs to the technical field of optical systems. The technical problems that the axial length compactness and the imaging quality of the visible light/infrared composite imaging system in the existing technology need to be improved are solved. The optical system of the present disclosure includes a main reflecting mirror, a first transmitting mirror, a third reflecting mirror, a fourth reflecting mirror, a second transmitting mirror, a third transmitting mirror and a fourth transmitting mirror. The optical system has a visible light panchromatic imaging function, a visible light multispectral imaging function and a long-wave infrared imaging function, which lowers the requirement of a space remote sensor for ground illumination conditions, realizes all-time space optical remote sensing reconnaissance and dynamic monitoring, and greatly improves the functional density and cost performance of a space optical load. The optical system has a compact structure, low distortion and good stray light inhibition, and is convenient to process, assemble and adjust.

A hybrid reflective/refractive HMD includes a structural frame, refractive optical lens elements, and optics housings coupled to the structural frame and positioned in front of a user's first and second eyes. Light-emitting visual sources and reflective optical surfaces are contained in the optics housings. Visual content is transmitted from light-emitting visual sources to the reflective optical surfaces. The visual content is reflected within the reflective optical surfaces at least four times without passing through a refractive optical lens element. The visual content is transmitted to the user's first eye or the user's second eye. Simultaneous with the transmission of the visual content to the user's first eye or the user's second eye, a real-world view of the outside surrounding environment is transmitted to the user's first eye or the user's second eye. The visual content is overlaid onto the real-world view of the outside surrounding environment.

A multiplexing module provided herein is configured to perform operations of receiving a plurality of laser pulses from a pulsed laser source; splitting each laser pulse into a plurality of beamlets; introducing a delay between each adjacent beamlet of the plurality of beamlets, such that the plurality of beamlets associated with a respective laser pulse of the plurality of laser pulses is distributed equally across a pulse repetition period associated with the pulsed laser source; changing a divergence of each subsequent beamlet of the plurality of beamlets associated with each respective laser pulse to introduce a distinguishing feature between each beamlet of the plurality of beamlet to cause each beamlet to focus on a different axial plane or lateral position of the sample; and outputting the plurality of beamlets associated with each respective laser pulse.