"Half-Life 2: Lost Coast" is a short, standalone level released by Valve Corporation in 2005 as a bonus for players of "Half-Life 2." It was initially developed to showcase the advanced graphical capabilities of the Source engine, particularly highlighting features like high-dynamic range lighting. The setting of "Lost Coast" is a coastal town in the "Half-Life 2" universe, where players take on the role of Gordon Freeman, the protagonist of the series.

An **Evil number** is a non-negative integer that has an even number of 1s in its binary representation. For example, the decimal number 3, which is represented in binary as `11`, has two 1s, thus making it an Evil number. In contrast, the number 5, which has a binary representation of `101`, has three 1s and is therefore not an Evil number.

The Orange Box is a video game compilation developed and published by Valve Corporation. Released in 2007, it includes five games: 1. **Half-Life 2**: A critically acclaimed first-person shooter that follows the story of Gordon Freeman as he battles alien forces and oppressive human regimes. 2. **Half-Life 2: Episode One**: The first of two episodic sequels to Half-Life 2, it continues the story immediately after the events of the main game.

"Prince of Darkness" is a 1987 horror film directed by John Carpenter. It is the second installment of Carpenter's informal "Apocalypse Trilogy," which also includes "The Thing" (1982) and "In the Mouth of Madness" (1994). The film combines elements of supernatural horror and sci-fi, exploring themes of evil, religion, and scientific inquiry. The plot centers around a group of researchers and students who are investigating a strange liquid contained in a church in Los Angeles.

A bandwidth-limited pulse is a signal or waveform that has been restricted in its frequency content or bandwidth. In the context of signal processing and telecommunications, a pulse is typically a transient signal that varies with time and can be characterized by its shape, duration, and the frequency components it contains. The key characteristics of bandwidth-limited pulses include: 1. **Frequency Limitation**: The pulse is designed such that its frequency spectrum does not exceed a certain maximum frequency.

A beam expander is an optical device that increases the diameter of a beam of light, typically a laser beam. It is used to improve the characteristics of the beam, such as its divergence, intensity distribution, and focusability. Beam expanders are commonly employed in various applications, including telecommunications, material processing, optical imaging, and laser manufacturing.

Gain-switching is a technique commonly used in laser technology to generate short and intense pulses of light. It is primarily employed in solid-state lasers and semiconductor lasers. The process involves rapidly varying the gain of the laser medium, which in turn affects the output intensity and timing of the emitted light.

Laser linewidth refers to the spectral width or range of wavelengths emitted by a laser light source. It's typically measured in terms of frequency (hertz) or wavelength (nanometers), and it quantifies the coherence of the laser light. A narrower linewidth indicates that the laser emits light over a very limited range of wavelengths, which corresponds to a highly coherent beam. The coherence is essential for various applications, including precision measurement, telecommunications, and interferometry.

Laser pumping is a process used to provide the necessary energy to excite the atoms or molecules in a gain medium, enabling them to emit coherent light through stimulated emission. The gain medium can be a solid, liquid, or gas, and typically contains atoms or ions that can be excited to higher energy states.

Photoionization mode refers to a process where an atom or molecule is ionized through the absorption of photons, typically in the ultraviolet (UV) or X-ray range. In this process, the energy of the incoming photons is sufficient to remove one or more electrons from the atom or molecule, resulting in the formation of positive ions.

Pyrromethene refers to a class of organic compounds that are characterized by a structure consisting of a pyrrole moiety bonded to a methylene group. These compounds are often used as dyes or fluorescent labels due to their unique photophysical properties. Pyrromethenes can exhibit strong fluorescence and are of interest in various applications including in the development of laser dyes, sensors, and in the field of fluorescence microscopy.

A Raman laser is a type of laser that utilizes the principle of Raman scattering to generate laser light. Raman scattering is a process where light interacts with the vibrational modes of a material, resulting in the scattering of light at different wavelengths. This interaction typically involves the photon energy change due to molecular vibrations or rotations in the medium.

An ultrashort pulse refers to a light pulse with an extremely short duration, typically on the order of femtoseconds (10⁻¹⁵ seconds) to picoseconds (10⁻¹² seconds). These pulses are generated using techniques such as mode-locking in lasers, which allows the beams of light to combine and create very short bursts of energy.

Laser gain media, also known simply as gain media, refers to the material within a laser that amplifies light through stimulated emission. When energy is supplied to this medium (typically through electrical or optical pumping), it gets excited to higher energy states. When these excited atoms or molecules return to their lower energy states, they emit photons, which can then stimulate further emissions in a process known as stimulated emission.

A space-based laser refers to a laser system that is positioned in space, often on a satellite or other spacecraft, and is designed for various applications. These applications can include communication, sensing, and military purposes, such as missile defense or targeting precision strikes. ### Key Features of Space-Based Lasers: 1. **Communication**: Space-based lasers can be used for high-bandwidth communication between satellites or between satellites and ground stations.

GRENOUILLE can refer to a few different things, depending on the context. In general, the term "grenouille" is French for "frog." However, in literature, it is often associated with the character Jean-Baptiste Grenouille from the novel "Perfume: The Story of a Murderer" by Patrick Süskind.

"Invisible Agent" could refer to several concepts depending on the context, such as: 1. **Film and Television**: "Invisible Agent" is a 1942 Universal Pictures film, which is a horror-comedy featuring a secret agent who is rendered invisible and uses his powers to fight against villains. 2. **Technology and Software**: In the context of technology, an "invisible agent" might refer to software or a system that operates without direct user interaction or awareness.

"The Invisible Man Appears" is a Japanese film released in 1957, directed by Akiyoshi Yamamoto. It is a science fiction story that serves as a follow-up to H.G. Wells' classic novel "The Invisible Man." The film incorporates elements of mystery and adventure, featuring a protagonist who gains the ability to become invisible and explores the implications and challenges that come with such a power.

"The Invisible Woman" is a 1940 American science fiction comedy film produced by Universal Pictures. It was directed by Edward Sutherland and is part of Universal's series of films featuring classic monsters, though it takes a lighter, comedic approach compared to other entries in the genre. The film tells the story of a beautiful woman named Kitty Carroll, played by Virginia Bruce, who is selected to become invisible in an experiment conducted by a scientist, Professor Gibbs, portrayed by John Barrymore.

"Die Another Day" is the soundtrack album for the James Bond film of the same name, which was released in 2002. The film is notable for being the 20th entry in the James Bond series and features a score composed by David Arnold, who had previously worked on the soundtracks for several other Bond films. The soundtrack includes a mix of orchestral pieces and songs, most famously featuring the title song "Die Another Day," performed by Madonna.