WO2023115381A1 - Procédé de réalisation d'un gain monoexcitonique dans des nanocristaux semi-conducteurs à l'aide de lasers à polarisation circulaire - Google Patents

Procédé de réalisation d'un gain monoexcitonique dans des nanocristaux semi-conducteurs à l'aide de lasers à polarisation circulaire Download PDF

Info

Publication number
WO2023115381A1
WO2023115381A1 PCT/CN2021/140414 CN2021140414W WO2023115381A1 WO 2023115381 A1 WO2023115381 A1 WO 2023115381A1 CN 2021140414 W CN2021140414 W CN 2021140414W WO 2023115381 A1 WO2023115381 A1 WO 2023115381A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
circularly polarized
intensity
gain
film sample
Prior art date
Application number
PCT/CN2021/140414
Other languages
English (en)
Chinese (zh)
Inventor
樊逢佳
唐贝贝
李桂海
杜江峰
Original Assignee
中国科学技术大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中国科学技术大学 filed Critical 中国科学技术大学
Priority to PCT/CN2021/140414 priority Critical patent/WO2023115381A1/fr
Publication of WO2023115381A1 publication Critical patent/WO2023115381A1/fr

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams

Definitions

  • the invention relates to the field of laser technology, in particular to a method for realizing single-exciton gain in semiconductor nanocrystals by using circularly polarized laser light.
  • Laser technology has a wide range of applications in communication, medical treatment, scientific research and other fields, and has great market demand.
  • Laser threshold is one of the core issues in the field of laser research. How to reduce the laser threshold and find new materials with low threshold is the focus of laser technology.
  • the basis of laser generation is the occurrence of amplified spontaneous emission.
  • the electrons in the excited state jump back to the valence band, and generate photons through spontaneous emission, and these photons further induce the excited state electrons to generate stimulated emission, so as to achieve the purpose of light amplification.
  • stimulated emission produces more photons than stimulated absorption, the remaining photons will be emitted in the form of laser light.
  • the incident light intensity just meets the laser emission condition is the threshold value.
  • semiconductor nanocrystals have become a research hotspot of optical gain materials due to their excellent luminescent properties such as continuously tunable wavelength, narrow-band emission, and high photoluminescence quantum yield.
  • electrons in the excited state will combine with valence band holes to form excitons, and the interaction between excitons will make them combine to form multi-excitons. Due to the existence of Auger recombination, the multi-exciton Energy is lost in the form of heat, resulting in inefficient stimulated emission and difficult lowering of the threshold.
  • the present invention provides a method for realizing single-exciton gain in semiconductor nanocrystals by using circularly polarized laser light.
  • the invention provides a method for realizing single-exciton gain in semiconductor nanocrystals by using circularly polarized laser light, comprising the following steps: using semiconductor nanocrystals to prepare thin film samples, so that the sample molecules are tightly packed and the position is fixed; using an ultraviolet-visible absorption spectrometer to measure The absorbance of the thin film sample; use a femtosecond laser and a circular polarizer to generate a beam of circularly polarized light, which is used as pump light to focus on the film sample; change the light intensity of the pump light, use another beam of circularly polarized light as the probe light, and detect The ground state bleaching signal intensity of the thin film sample; determine whether the ground state bleaching signal intensity is equal to the absorbance, and if so, determine that the critical light intensity of the pump light is the gain threshold of the single excitons.
  • the semiconductor nanocrystal is a perovskite nanocrystal material
  • the perovskite nanocrystal material includes CsPbBr 3 , CsPbI 3 , MAPbI 3 or MAPbBr 3 .
  • the step of preparing the thin film sample includes: using a spin coater to spin coat the solution sample on a glass sheet, and after the solvent evaporates, the sample molecules are tightly packed and the position is fixed.
  • measuring the absorbance of the film sample includes: measuring the absorbance of the film sample in the wavelength range of 400nm to 600nm, and the absorbance is measured according to the following formula:
  • ⁇ 0 represents the absorbance of the film sample in the wavelength range of 400nm–600nm; I 0 represents the original intensity of white light; I represents the intensity of white light passing through the film sample without pump light excitation.
  • the wavelength range of the pump light is 450nm-515nm.
  • the wavelength range of the detection light is 450nm-550nm.
  • ground-state bleaching signal intensity is the change in the absorption of the probe light by the thin film sample under the conditions of pump light and no pump light excitation; the ground-state bleaching signal intensity is measured according to the following formula:
  • ⁇ represents the ground state bleaching signal intensity of the film sample
  • I represents the intensity of the probe light passing through the film sample without pump light excitation
  • I 1 represents the intensity of the probe light passing through the film sample under the excitation of pump light after the strength.
  • the invention provides a method for realizing single-exciton gain in semiconductor nanocrystals by using circularly polarized laser light.
  • the polarization of the excitation light By changing the polarization of the excitation light, the variation of the absorption and stimulated emission of the film sample after excitation with the incident power is detected. , compared with the absorbance, the threshold of optical gain is lower when excited by circularly polarized light, indicating that the gain is dominated by single excitons.
  • Figure 1 schematically shows a flow chart of a method for realizing single-exciton gain in semiconductor nanocrystals using circularly polarized laser light
  • Figure 2 schematically illustrates a simplified setup diagram of a method for achieving single-exciton gain in semiconductor nanocrystals
  • Figure 3 schematically shows the principle of circularly polarized light generating single-exciton gain
  • Figure 4 schematically shows the test results when the pump light and the probe light have the same/opposite circular polarization
  • Fig. 5 schematically shows the gain threshold diagram under circularly polarized light/non-circularly polarized light excitation.
  • connection In the present invention, unless otherwise clearly specified and limited, the terms “installation”, “connection”, “connection”, “fixation” and other terms should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, Or integrated; it can be mechanically connected, or electrically connected, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components.
  • fixing and other terms should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, Or integrated; it can be mechanically connected, or electrically connected, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components.
  • Fig. 1 schematically shows a flowchart of a method for realizing single exciton gain in semiconductor nanocrystals by using circularly polarized laser light.
  • the method for realizing single-exciton gain in semiconductor nanocrystals by using circularly polarized laser includes the following steps:
  • Step S1 using semiconductor nanocrystals to prepare a thin film sample, so that the sample molecules are tightly packed and the position is fixed;
  • Step S2 using an ultraviolet-visible absorption spectrometer to measure the absorbance of the film sample
  • Step S3 using a femtosecond laser and a circular polarizer to generate a beam of circularly polarized light, which is used as pump light to focus on the film sample;
  • Step S4 changing the light intensity of the pump light, using another beam of circularly polarized light as the detection light to detect the ground state bleaching signal intensity of the film sample;
  • Step S5 judging whether the intensity of the ground state bleaching signal is equal to the absorbance, and if so, determining that the critical light intensity of the pump light is the gain threshold of the single excitons.
  • the semiconductor nanocrystal is a perovskite nanocrystal material
  • the perovskite nanocrystal material includes CsPbBr 3 , CsPbI 3 , MAPbI 3 or MAPbBr 3 .
  • the step of preparing a thin film sample includes: using a spin coater to spin coat the solution sample on a glass plate, and after the solvent evaporates, the sample molecules are tightly packed and the position is fixed, so as to generate laser light emitted in a specific direction.
  • measuring the absorbance of the film sample includes: measuring the absorbance of the film sample in the wavelength range of 400nm to 600nm, and the absorbance is measured according to the following formula:
  • ⁇ 0 represents the absorbance of the film sample in the wavelength range of 400nm–600nm; I 0 represents the original intensity of white light; I represents the intensity of white light passing through the film sample without pump light excitation.
  • the wavelength range of the pump light is 450nm-515nm.
  • the wavelength range of the detection light is 450nm ⁇ 550nm.
  • the ground-state bleaching signal intensity is the change in the absorption of the probe light by the film sample under the conditions of pump light and no pump light excitation; the ground-state bleaching signal intensity is measured according to the following formula:
  • ⁇ represents the ground state bleaching signal intensity of the film sample
  • I represents the intensity of the probe light passing through the film sample without pump light excitation
  • I 1 represents the intensity of the probe light passing through the film sample under the excitation of pump light after the strength.
  • the gain generated by the sample is measured by using absorption spectrum and transient absorption spectrum.
  • the detection light intensity that passes through the sample when there is pump light is obtained through the experimental device of transient absorption spectroscopy.
  • the gain threshold is significantly lower when excited with circularly polarized light, indicating that the gain is dominated by single excitons.
  • the present invention uses absorption spectrum and transient absorption spectrum to measure the gain produced by the sample.
  • the specific device is as follows: the 1030nm femtosecond pulse generated by the femtosecond laser is divided into two beams after passing through the beam splitter, and one of them passes through the optical parametric amplifier. Continuously adjustable as pump light. The other beam passes through the BBO crystal ( ⁇ -phase barium metaborate crystal, ⁇ -BaB 2 O 4 ) and the sapphire crystal, and then the wavelength range is expanded to 450nm-550nm as the probe light.
  • BBO crystal ⁇ -phase barium metaborate crystal, ⁇ -BaB 2 O 4
  • the sapphire crystal the wavelength range is expanded to 450nm-550nm as the probe light.
  • the absorption of the probe light by the sample will decrease.
  • the intensity of the probe light passing through the sample will be greater than that transmitted through the sample without pump light excitation.
  • the detection light intensity is called the ground state bleaching signal.
  • Figure 2 schematically shows a simplified setup diagram of a method for achieving single-exciton gain in semiconductor nanocrystals.
  • a simplified experimental setup for single exciton gain measurement as shown in Fig. 2 was adopted. After the pump light passes through the circular polarizer, a beam of left-handed circularly polarized light is generated, which is incident on the sample at a certain angle; then, another beam of left-handed circularly polarized light is focused on the sample by using a linear polarizer and a 1/4 wave plate. The transmitted light is collected after the sample to detect the ground state bleaching signal intensity of the sample. Combining this ground state bleaching signal intensity with the absorbance, the gain threshold can be calculated.
  • achromatic prisms are mainly used for chromatic aberration correction and light focusing.
  • the optical fiber collector is mainly used to collect the light required for the test, effectively improving the light collection efficiency.
  • Figure 3 schematically shows the principle of circularly polarized light generating single-exciton gain.
  • the electron spin can take ⁇ 1/2.
  • the nanocrystals in the ground state will absorb, reducing the intensity of the transmitted light, while the nanocrystals in the single-exciton state will not only absorb part of the photons, but also generate part of the photons due to stimulated radiation, Since the number of photons absorbed and generated are equal, the light intensity does not change when the excitation light passes through the nanocrystal, and the nanocrystal is transparent to the excitation light.
  • the nanocrystal when the nanocrystal is in the biexciton state, the conduction band population has been filled and the population inversion is realized, so the nanocrystal will not absorb the excitation light, but will emit additional photons due to the stimulated radiation, resulting in gain.
  • non-polarized light excitation when the number of biexciton nanocrystals generated after excitation is greater than the number of nanocrystals in the ground state, photons can be emitted.
  • the transition selection rule In the case of circularly polarized light excitation, only electrons satisfying the transition selection rule can be excited to the conduction band. Therefore, only when the nanocrystal is in the ground state, it will absorb the excitation light.
  • the condition for gain to occur is that the number of nanocrystals in the single exciton state is greater than the number of nanocrystals in the ground state.
  • the threshold condition to be satisfied is lower, and the gain is mainly dominated by single excitons.
  • Fig. 4 schematically shows the test results when the pump light and the probe light have the same/opposite handedness circular polarization.
  • Fig. 5 schematically shows the gain threshold diagram under circularly polarized light/non-circularly polarized light excitation.
  • Embodiment 1 is a spin lifetime test.
  • left-handed and right-handed circularly polarized light are respectively used to detect the ground state bleaching signal of the sample, and the experimental results shown in FIG. 4 can be obtained.
  • the signal detected by using left-handed circularly polarized light rises rapidly to the maximum value, while the signal detected by right-handed circularly polarized light rises slowly, and the two coincide after 7 ps, which indicates that the pumping
  • the light generates electrons with an angular momentum of -1/2. Due to the transition selection rule, only the left-handed circularly polarized light can detect the corresponding ground-state bleaching signal.
  • the polarization degree generated by the excitation light can be obtained as 75% through the amplitude difference of the two signals. This shows that within 7ps, the polarization of electrons can be achieved by using circularly polarized light excitation, reducing the degeneracy of energy levels, and only generating single excitons, which reflects the feasibility of single exciton gain.
  • Fig. 5 shows the graph of the ground state bleaching signal versus power under circularly polarized light/non-circularly polarized light excitation.
  • the embodiment of the present invention provides a method for realizing single-exciton gain in semiconductor nanocrystals by using circularly polarized laser light.
  • the absorption and stimulated emission of the thin film sample after excitation vary with the incident power.
  • the threshold of optical gain is lower when excited by circularly polarized light, indicating that the gain is dominated by single excitons.

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

Procédé de réalisation d'un gain monoexcitonique dans des nanocristaux semi-conducteurs à l'aide de lasers à polarisation circulaire, se rapportant au domaine technique des lasers. Le procédé comprend les étapes suivantes : la préparation d'un échantillon de couche mince à partir de nanocristaux semi-conducteurs, des molécules d'échantillon étant emballées de manière serrée et dense et fixées en position (S1) ; la mesure de l'absorbance de l'échantillon de couche mince à l'aide d'un spectromètre d'absorption visible par ultraviolets (S2) ; la génération d'un faisceau lumineux à polarisation circulaire à l'aide d'un laser femtoseconde et d'un polariseur circulaire, et la focalisation du faisceau lumineux à polarisation circulaire sur l'échantillon de couche mince en tant que lumière de pompage (S3) ; la modification de l'intensité de la lumière de pompage, et la mesure, à l'aide d'un autre faisceau lumineux à polarisation circulaire en tant que lumière de sonde, de l'intensité d'un signal de blanchiment d'état fondamental de l'échantillon de couche mince (S4) ; et la détermination quant à savoir si l'intensité du signal de blanchiment d'état fondamental est égale à l'absorbance, et si tel est le cas, la détermination que l'intensité de lumière de seuil de la lumière de pompage est un seuil de gain monoexcitonique (S5).
PCT/CN2021/140414 2021-12-22 2021-12-22 Procédé de réalisation d'un gain monoexcitonique dans des nanocristaux semi-conducteurs à l'aide de lasers à polarisation circulaire WO2023115381A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/140414 WO2023115381A1 (fr) 2021-12-22 2021-12-22 Procédé de réalisation d'un gain monoexcitonique dans des nanocristaux semi-conducteurs à l'aide de lasers à polarisation circulaire

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/140414 WO2023115381A1 (fr) 2021-12-22 2021-12-22 Procédé de réalisation d'un gain monoexcitonique dans des nanocristaux semi-conducteurs à l'aide de lasers à polarisation circulaire

Publications (1)

Publication Number Publication Date
WO2023115381A1 true WO2023115381A1 (fr) 2023-06-29

Family

ID=86901002

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/140414 WO2023115381A1 (fr) 2021-12-22 2021-12-22 Procédé de réalisation d'un gain monoexcitonique dans des nanocristaux semi-conducteurs à l'aide de lasers à polarisation circulaire

Country Status (1)

Country Link
WO (1) WO2023115381A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090116524A1 (en) * 2007-05-17 2009-05-07 Klimov Victor I Single-exciton nanocrystal laser
CN103344574A (zh) * 2013-06-27 2013-10-09 南京邮电大学 有机薄膜光增益性能测试装置
CN103837239A (zh) * 2014-03-03 2014-06-04 哈尔滨工业大学 基于反射光波形测量非聚焦泵浦的受激布里渊散射阈值的装置及阈值测量方法
EP2887044A1 (fr) * 2013-12-19 2015-06-24 Rigas Tehniska Universitate Procédé et système de mesure de puissance de seuil par diffusion de brillouin stimulée
CN110896129A (zh) * 2018-09-13 2020-03-20 中国科学院大连化学物理研究所 基于钙钛矿纳米晶与并苯分子材料的多激子解离异质结
US20210167566A1 (en) * 2019-12-02 2021-06-03 Shanxi University Device and method for measuring thermal load caused by excited state absorption in laser gain crystal

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090116524A1 (en) * 2007-05-17 2009-05-07 Klimov Victor I Single-exciton nanocrystal laser
CN103344574A (zh) * 2013-06-27 2013-10-09 南京邮电大学 有机薄膜光增益性能测试装置
EP2887044A1 (fr) * 2013-12-19 2015-06-24 Rigas Tehniska Universitate Procédé et système de mesure de puissance de seuil par diffusion de brillouin stimulée
CN103837239A (zh) * 2014-03-03 2014-06-04 哈尔滨工业大学 基于反射光波形测量非聚焦泵浦的受激布里渊散射阈值的装置及阈值测量方法
CN110896129A (zh) * 2018-09-13 2020-03-20 中国科学院大连化学物理研究所 基于钙钛矿纳米晶与并苯分子材料的多激子解离异质结
US20210167566A1 (en) * 2019-12-02 2021-06-03 Shanxi University Device and method for measuring thermal load caused by excited state absorption in laser gain crystal

Similar Documents

Publication Publication Date Title
Liu et al. Near-resonant Raman amplification in the rotational quantum wave packets of nitrogen molecular ions generated by strong field ionization
CN110190500A (zh) 一种用于窄带飞秒激光器的光参量放大方法及装置
US20210203352A1 (en) Method of coding based on transition of lasing and non-lasing states of optical structure
WO2023174034A1 (fr) Système laser picoseconde à haute luminosité
Xie et al. Vibrational population transfer between electronic states of N 2+ in polarization-modulated intense laser fields
McKay et al. High power tungstate-crystal Raman laser operating in the strong thermal lensing regime
Sandu et al. High-peak power, passively Q-switched, composite, all-polycrystalline ceramic Nd: YAG/Cr4+: YAG lasers
JP5196436B2 (ja) テラヘルツ波発生装置及びテラヘルツ波発生方法
CN105159008B (zh) 铌酸镓镧晶体作为中红外波段的非线性光学器件的应用
WO2023115381A1 (fr) Procédé de réalisation d'un gain monoexcitonique dans des nanocristaux semi-conducteurs à l'aide de lasers à polarisation circulaire
Murari et al. Ho: YLF amplifier with Ti: Sapphire frontend for pumping mid-infrared optical parametric amplifier
Liu et al. High-Power Laser Performance of ${\hbox {Yb:}}{\hbox {YAl}} _ {3}({\hbox {BO}} _ {3}) _ {4} $ Crystals Cut Along the Crystallographic Axes
Smith et al. Observations of noncollinear phase matching in optical parametric noise emission
Jacinto et al. Microstructuration induced differences in the thermo-optical and luminescence properties of Nd: YAG fine grain ceramics and crystals
CN114268019A (zh) 利用圆偏振激光实现半导体纳米晶中单激子增益的方法
Wang et al. Populations of B 2 Σ u+ and X 2 Σ g+ electronic states of molecular nitrogen ions in air determined by fluorescence measurement
Yan et al. 926 nm laser operation in Nd: GdNbO4 crystal based on 4F3/2→ 4I9/2 transition
Brandt et al. Inband pumped Er: Lu2O3 and Er, Yb: YVO4 lasers near 1.6 μm for CO2 LIDAR
CN110048300B (zh) 基于磷酸钆晶体的激光器
CN112054375A (zh) 一种电子-声子耦合的高集成全固态激光波长调控方法及激光器
Zhao et al. Solar-pumped 1061-/1064-nm dual-wavelength Nd: YAG monolithic laser
CN110233418A (zh) 一种可调脉宽短脉冲激光器
CN111045272A (zh) 一种共线圆偏振长波双色场产生太赫兹波的装置及方法
Mukhin et al. One kilohertz cryogenic disk laser with high average power
Lü et al. Fine wavelength control in 1.3 μm Nd: YAG lasers by electro-optical crystal lens

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21968530

Country of ref document: EP

Kind code of ref document: A1