What extraneous quantum efficiency is precisely defined

External quantum efficiency: light-emitting diode (LED) is known as the 21st century lighting source, which has the advantages of energy saving, environmental protection and long service life compared with traditional light sources, and its main application fields include: traffic indicators, outdoor full-color displays, LCD backlighting, and daily lighting and decorative lighting, etc., which are the lighting devices with higher brightness and lower energy consumption required for social development in the future.

However, at present, in order to completely replace other light sources in the field of lighting, LED also needs to solve the problems of improving light efficiency, reducing costs, reducing chip heat, and improving the service life of LEDs, and these problems are all restricted by the low quantum efficiency of LEDs. The low external quantum efficiency of LED is mainly due to the limitation of the total reflection condition of the interface between its surface and air, which leads to its low light extraction efficiency. At present, there are many ways to improve the efficiency of LED light extraction in the world, such as surface roughening, making Bragg reflective layer, making two-dimensional photonic crystals, etc.

Among these methods, the use of two-dimensional photonic crystals to improve the external quantum efficiency of LEDs has become one of the research hotspots at present, which has the advantages of simple process and high optical extraction efficiency. At present, the international methods for making photonic crystal LEDs have their own advantages and disadvantages, and there is no method that can conveniently, quickly and low-cost to make photonic crystal patterns with large area and small lattice constants. This makes it impossible for photonic crystal LEDs to be industrially produced.

The use of laser holography technology to make photonic crystals on photoresist has the advantages of low cost, short production cycle, and convenient production of large-area photonic crystals. It is also made using holographic optics (HOE).

External quantum efficiency (EQE), the ratio of the number of charge carriers of a solar cell to the number of photons of a certain energy incident on the surface of the solar cell.

Quantum communication.

a. Planck introduced the energy particle into physics in 1900, breaking the traditional concept of "continuous change of energy", so A is wrong;

b. Einstein was the first to realize the significance of energy particles, proposed the photon theory to explain the experimental law of the photoelectric effect, and successfully explained the phenomenon of the photoelectric effect, so B is correct;

C. Bohr introduced the quantum concept into the atomic field for the first time, and proposed the concepts of stationary state and transition, so C is wrong;

d. De Broglie boldly extended the wave-particle duality of light to physical particles, and predicted that physical particles also have fluctuations, so d was wrong;

Therefore, b

Quantum measurement refers to the use of special effects of quantum to be correct.

1. In quantum mechanics, the so-called "measurement" needs to be more rigorously defined, and it is especially called quantum measurement. Quantum measurement is different from the measurement in classical mechanics in that it has an impact on the subsystem being measured, such as changing the state of the subsystem being measured.

Second, quantum systems in the same state may obtain completely different results when measured, and these results conform to a certain probability distribution.

3. Quantum measurement is the core problem of the quantum mechanical interpretation system, and the interpretation of quantum mechanics has not yet been concluded. In addition to the experimental physics considerations, the dimensions of quantum measurements also include philosophical perspectives.

4. Classification of quantum measurements.

1. Mathematical form.

Unlike measurements in classical physics, quantum measurements do not exist independently of the physical system being observed, but rather are part of the physical system itself, and the measurements made interfere with the state of the system.

2. General form.

The third clause of the quantum public is the definition of the liter under the measurement. Quantum measurements can be represented by a set of measurement operators, which act on the state space of the system. The serial number M of the measurement operator M indicates the different results of the measurement.

3. If the system is in a state before the measurementpsi>

1) Then the probability of getting the result m after measurement is: p( m ).

2) After measurement, the state of the system becomes: m m|psi>/sqrt()

3) The measurement operator must meet the following completeness conditions: sum m(m* mm m)=i

4) The above completeness condition is equivalent to the following equation, that is, the completeness condition determines the sum of the probabilities of each result measured to be 1:

1=sum_m(p_m)=sum_m()。

When photons are incident on the surface of the photosensitive device, some of the photons will excite the photosensitive material to generate electron-hole pairs to form an electric current, and the ratio of the generated electrons to the number of photons in all incident limb signals is called the external quantum efficiency (EQE).

External quantum efficiency (EQE) is one of the main performance indicators of photodetectors. Its value is the ratio of the number of collected electrons to the number of incident photons.