World’s fastest single-shot camera confirms how flames form soot

World’s fastest single-shot camera confirms how flames form soot

Subject: Environment

Section: Climate Change

Context: Scientists from Germany and the U.S. have built the world’s fastest single-shot laser camera – 1,000x faster than its predecessors at capturing extremely short-lived events.

More on the News:

• Scientists used the camera to provide the most precise view yet of how a hydrocarbon flame produces soot, which can teach us about how this important climate pollutant is produced in kitchen stoves, car engines, and wildfires.
• The device’s technique is called laser-sheet compressed ultrafast photography (LS-CUP).

Soot or Black Carbon:

• Soot is a form of particulate air pollutant, produced from incomplete combustion.
• Soot, commonly known as Black carbon.
• Black carbon is a solid particle or aerosol (though not a gas) that contributes to warming of the atmosphere.
• India and China are the largest emitters of black carbon in the world.
• The Indo-Gangetic plains will become the largest contributor of black carbon, with about 20 per cent from biofuels, 40 per cent from fossil fuels and about 40 per cent from biomass burning.

Impacts of Soot:

• Black carbon warms the earth by absorbing heat in the atmosphere and by reducing albedo (the ability to reflect sunlight) when deposited on snow and ice.
• BC is the strongest absorber of sunlight and heats the air directly.
• It emits infra-red radiation that increases the temperature.
• In addition, it darkens snowpack and glaciers through deposition and leads to melting of ice and snow (black carbon is contributing to the melting of Himalayan Glaciers).
• Regionally, BC disrupts cloudiness and monsoon rainfall.
• Black carbon stays in the atmosphere for only several days to weeks.

Laser-sheet compressed ultrafast photography

• Laser-sheet compressed ultrafast photography (LSCUP) is a high-speed imaging technique that can capture ultrafast events, such as the motion of shock waves, explosions, and fluid dynamics. It is a variation of compressed ultrafast photography (CUP), which is based on the principle of temporal imaging.
• In LSCUP, a laser pulse is used to create a thin sheet of light, which illuminates the object being imaged. The object is then imaged by a camera with a fast shutter speed, typically in the picosecond or femtosecond range.
• The laser sheet and the camera are synchronized so that the camera captures the object at different times as it moves through the laser sheet. The resulting images can be combined to create a 3D movie of the object’s motion.

Advantage of Laser-sheet compressed ultrafast photography

• High temporal and spatial resolution: LSCUP can capture ultrafast events with high temporal and spatial resolution, enabling researchers to study dynamic processes in detail.
• Non-invasive imaging: LSCUP is a non-invasive imaging technique that does not require physical contact with the object being imaged. This is especially useful for studying delicate biological samples or explosive events.
• 3D imaging: LSCUP can capture multiple images of an object from different angles, allowing for the creation of a 3D movie of the object’s motion.

Disadvantage of Laser-sheet compressed ultrafast photography

• Costly equipment: LSCUP requires specialized equipment, such as ultrafast lasers and high-speed cameras, which can be expensive.
• Complex setup: Although LSCUP is relatively easy to set up compared to other high-speed imaging techniques, it still requires careful calibration and synchronization of the laser sheet and camera.
• Limited sample types: LSCUP may not be suitable for all types of samples, particularly those that are opaque or have complex structures that can block or scatter the laser sheet.
• Data processing: LSCUP generates a large amount of data, and processing this data can be time-consuming and computationally intensive.