A depth-sensitive system for monitoring for and detecting a predefined condition at a specific location within a visually monitored portion of an area. Plural depth-sensitive cameras are oriented with respect to the area whereby each camera has a field of view within the area that at least partially overlaps with the field of view of another of the plural cameras. The combined field of view encompasses all portions of interest of the area. A system for providing a notification of the visual detection of a predefined condition at a particular location or set of locations within an area of interest is provided, as is a system for generating a visual representation of human activity at one or more specific locations within an area of interest.

A recording head includes a substrate, a read transducer, a waveguide core, and a near-field transducer at an end of the waveguide core proximate a media-facing surface. The recording head includes a magnetic write pole and coil. A laser diode unit with one or more non-self-supporting layers of crystalline material region is transfer printed between layers of the recording head.

A heat-assisted recording head is moved onto a ramp such that the recording head is thermally isolated from a moving disk. A heating device is activated on the recording head to cause the recording head to obtain a high temperature that is not obtainable when proximate to the moving disk. The recording head is moved over the moving disk such that the recording head reaches an operating temperature that is below the high temperature. One or more temperatures between the high temperature and the operational temperature are determined at which a laser of the recording head experiences mode-hopping. The one or more temperatures are stored and accessed by a controller to mitigate mode hopes during an operation of the recording head.

A heat-assisted recording head is moved onto a ramp such that the recording head is thermally isolated from a moving disk. A heating device is activated on the recording head to cause the recording head to obtain a high temperature that is not obtainable when proximate to the moving disk. The recording head is moved over the moving disk such that the recording head reaches an operating temperature that is below the high temperature. One or more temperatures between the high temperature and the operational temperature are determined at which a laser of the recording head experiences mode-hopping. The one or more temperatures are stored and accessed by a controller to mitigate mode hopes during an operation of the recording head.

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a write assist element. Data is written to the disk using the write assist element. A protrusion of the head toward the disk is measured periodically, and an abnormality with the write assist element is detected when a slope of the protrusion measurements indicates the protrusion is increasing.

The present invention is in the field of an atomic scale data storage device which uses vacancy manipulation, a method of providing said device, and a method of operating said device. Prior art mass data storage devices typically rely on magnetic materials forming discrete arrays or on nanoscale transistors. Further examples are e.g. optical systems such as a DVD and a compact disk. These devices and systems have a large, but for some applications still limited, storage capacity.

A fabrication method of a multi-core fiber Bragg grating (FBG) probe for measuring structures of a micro part based on the capillary self-assembly technique, wherein the diameter of the fiber (6) inscribed with FBG is reduced using a mechanical method or an etch method by the hydrofluoric acid; the fibers (6) inscribed with FBG, whose diameter has been reduced, are inserted into a tube (7) through its terminal with an inner taper angle; the FBG terminals of these fibers (6) are immersed into the UV adhesive (10) of a low viscosity and the UV adhesive (10) is raised in the gaps between the fibers (6); or the UV adhesive is dropped on these fibers (6) and the capillary bridge between the fibers (6) is formed; a most compact structure of the fiber bundle is formed as a result of the capillary self-assembly; the fiber bundle is cured using a UV light and the multi-core FBG (11) is therefore formed; the terminal of the multi-core FBG (11) is polished with an optic fiber polishing machine and then a spherical tip is fabricated with the melting fiber method or the installation method of a micro ball; therefore, a multi-core FBG (11) probe can be achieved. The method features low crosstalk between signal of FBG, inexpensive and low insertion loss.

Data can be transmitted and represented by signal gaps in a transmission, the gaps having various attributes. In various examples, data points are encoded and represented by the attributes of said signal gaps. Various attributes of such gaps, including duration, pattern, quantity, time, and/or coordination with a gap in another signal can represent data.

An apparatus includes an input coupler configured to receive light excited by a light source. A near-field transducer (NFT) is positioned at a media-facing surface of a write head. A layered waveguide is positioned between the input coupler and the NFT and configured to receive the light output from the input coupler in a transverse electric (TE) mode and deliver the light to the NFT in a transverse magnetic (TM) mode. The layered waveguide comprises a first layer extending along a light-propagation direction. The first layer is configured to receive light from the input coupler. The first layer tapers from a first cross track width to a second cross track width where the second cross track width is narrower than the first cross track width. The layered waveguide includes a second layer that is disposed on the first layer. The second layer has a cross sectional area in a plane perpendicular to the light propagation direction that increases along the light propagation direction. The cross sectional area of the second layer is smaller proximate to the input coupler and larger proximate to the NFT. The layered waveguide includes an interface between the first layer and the second layer, the interface comprises a curve.

An apparatus comprises a laser diode configured to generate modulated light during a write operation in response to receiving modulated current having a mean amplitude that varies or is constant. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A writer heater of the slider is configured to receive power during the write operation having a magnitude that varies or is constant. A sensor is situated on or within the slider. The sensor is configured to produce a sensor signal representative of output optical power of the laser diode. Measuring circuitry is coupled to the sensor and configured to measure a change in the sensor signal indicative of a laser mode hop during the write operation.