A functional polymer / liquid crystal composite semiconductor micro-nano laser and a preparation method thereof

Abstract

This invention discloses a functional polymer / liquid crystal composite semiconductor micro / nano laser and its fabrication method. This laser utilizes the Rayleigh instability of the cylindrical liquid interface to form a functional polymer / liquid crystal spindle structure with a specific morphology on the surface of semiconductor micro / nanowires. This constructs a composite optical microcavity that enhances optical field confinement and suppresses radiation loss, thereby improving the quality factor of the resonant cavity, compressing the resonant linewidth, and lowering the laser threshold. Furthermore, by controlling the size parameters of the functional polymer / liquid crystal spindle and its coverage position on the semiconductor micro / nanowire surface, effective control of the resonant mode is achieved. Based on the relevant properties of the semiconductor material and the polymer / liquid crystal cladding material, this invention exhibits excellent photostability under pulsed light pumping and long-term detection conditions, significantly enhancing the device's specific recognition capability of analyte molecules and its high-sensitivity sensing performance.

Description

Technical Field

[0001] This invention relates to the field of optics, specifically to a functional polymer / liquid crystal composite semiconductor micro / nano laser and its fabrication method. Background Technology

[0002] Micro- and nano-lasers, relying on stimulated emission amplification, possess significant advantages such as high energy density and ultra-narrow spectral linewidth, demonstrating irreplaceable application potential in fields such as high-sensitivity sensing, precision detection, and high-resolution imaging. Among them, polymer / liquid crystal micro- and nano-lasers fully utilize the excellent optical tunability, structural flexibility, chemical stability, and functionalizability of polymer and liquid crystal materials, achieving stable operation in liquid or complex environments. They also possess strong tunability, biocompatibility, and the ability to flexibly control the laser mode and emission wavelength, showing broad application prospects in fields such as high-sensitivity biochemical sensing, specific molecular recognition, on-chip light sources, microfluidic detection, and integrated photonic devices.

[0003] However, existing micro / nano laser systems mostly rely on organic dyes as gain media, which are prone to photobleaching under strong light pumping or long-term excitation conditions. This leads to unstable laser output, increased threshold, and limited device lifetime, severely restricting their development in applications such as continuous pumping and biochemical detection. Semiconductor micro / nanowires, with their excellent anti-photobleaching properties, as well as high optical gain and photothermal stability, provide an important alternative for constructing dye-free micro / nano laser systems. However, conventional semiconductor micro / nanowires still suffer from insufficient light field confinement, decreased resonant cavity quality factor, and limited surface functionalization in liquid environments, making it difficult to simultaneously meet the requirements of low threshold, high optical stability, tunability, and functional applications. Summary of the Invention

[0004] The purpose of this invention is to provide a method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser, comprising the following steps:

[0005] Step 1) Based on micro-nano manipulation under a microscope, a single semiconductor micro-nano wire is partially suspended and fixed on a suspension support structure.

[0006] Step 2) Using a fiber optic probe that moves precisely in three-dimensional space, the polymer / liquid crystal is placed at a predetermined position on the semiconductor micro / nanowire.

[0007] Step 3) Using an optical fiber probe, liquid polymer / liquid crystal droplets are slid along the axial direction of the semiconductor micro / nanowire, so that the polymer / liquid crystal droplets form one or more polymer spindles on the semiconductor micro / nanowire under the driving force of surface tension and Rayleigh instability.

[0008] Furthermore, in step 1), the semiconductor micro / nanowires generate spontaneous or stimulated emission under optical pumping conditions and are amplified.

[0009] The suspension support structure includes a base and a mesh support structure arranged on the base.

[0010] Furthermore, in step 2), if the polymer / liquid crystal solidifies within time T, solvent vapor for dissolving the polymer / liquid crystal is introduced into the assembly area via a syringe.

[0011] Furthermore, in step 3), during the formation of the polymer spindle, the transverse diameter and axial length of the polymer spindle are adjusted by controlling the volume of the polymer / liquid crystal material.

[0012] Furthermore, the polymer spindle is a microcavity structure that is thick in the middle and gradually thins at both ends, forming a whispering-gallery mode. This constrains the light field in the cross-sectional direction and axial direction of the semiconductor micro / nanowire and allows it to propagate cyclically along the cavity of the microcavity structure.

[0013] Furthermore, in step 3), when using a liquid polymer, the step of forming one or more polymer spindles on semiconductor micro / nanowires includes:

[0014] Polymer microwires are picked up from liquid polymer using an optical fiber probe, allowing the polymer microwires to come into contact with semiconductor micro / nanowires.

[0015] Solvent vapor is introduced into the environment where the semiconductor micro / nanowires are located and acts on the polymer microwires, causing the polymer microwires to soften.

[0016] After softening, the polymer microwires spontaneously rearrange and shrink along the axial direction of the semiconductor micro / nanowires, and self-assemble into a coating structure with spindle-shaped geometric features on the semiconductor micro / nanowires, thereby forming one or more polymer spindles on the semiconductor micro / nanowires.

[0017] Furthermore, in step 3), when using liquid crystal, the step of forming one or more polymer spindles on semiconductor micro / nanowires includes:

[0018] Liquid crystals were introduced onto the surface of semiconductor micro- and nanowires using a micropipette.

[0019] Withdrawing the pipette, under the combined effects of nanowire curvature, suspended geometry constraints, and interface energy minimization, the liquid crystal material evolves into a localized liquid crystal droplet structure attached to the nanowire surface, thereby forming one or more polymer spindles on the semiconductor micro / nanowire.

[0020] The laser obtained according to the preparation method is a micro / nano laser with semiconductor micro / nano wires as the gain medium and polymer spindles as the resonant cavity.

[0021] Furthermore, when the stimulated emission gain obtained by light during its round-trip propagation within the polymer spindle cavity exceeds the cavity loss, a specific longitudinal mode is preferentially amplified and forms a stable oscillation, outputting laser radiation at the interface between the polymer spindle and air.

[0022] Furthermore, when the laser is working, when the light propagates to the polymer spindle region, the abrupt change in refractive index between the polymer / liquid crystal and air causes some of the laterally propagating light to undergo total internal reflection at the sidewalls of the semiconductor micro / nanowires, forming a lateral light field confinement.

[0023] Meanwhile, in the axial direction, the polymer spindle structure introduces an equivalent focusing effect, causing the beam inside the cavity to continuously converge during the round-trip propagation process, forming a longitudinal optical field constraint.

[0024] The technical effects of this invention are undeniable. Addressing the common problems of low cavity quality factor, high laser threshold, photobleaching of organic dyes, and insufficient device stability in existing micro / nano lasers operating in liquid or complex environments, this invention proposes a functional polymer / liquid crystal composite whispering-gallery mode micro / nano laser structure and its implementation method. By introducing functional polymer / liquid crystal microstructures with specific morphologies onto the surface of semiconductor micro / nano wires, and fully leveraging the high optical stability and high optical gain characteristics of semiconductor materials, a high-quality whispering-gallery mode optical resonator based on a spindle structure is constructed. This achieves low-threshold, narrow-linewidth micro / nano laser output that can operate stably in liquid environments. Furthermore, by utilizing the excellent chemical stability and functionalizability of polymer / liquid crystal materials, this invention can further endow the device with a high-specificity recognition capability for the target molecules, significantly improving its sensing performance.

[0025] In summary, the composite microcavity structure proposed in this invention is realized using a relatively simple and controllable process, without the need for complex nano-etching or high-vacuum processing conditions. It has the advantages of strong tunability of structural parameters and high compatibility with various semiconductor material systems, providing a solid foundation for constructing highly specific, highly stable, and highly sensitive biosensing probes. Furthermore, it provides a novel high-performance optical platform for applications such as single-cell sensing, molecular dynamics monitoring, and trace biochemical detection in liquid environments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the principle of the present invention;

[0027] Figure 2 The steps for preparing the composite structure in this invention are as follows: a) transferring CdS nanowires onto a copper grid and suspending them with an optical fiber probe; b) transferring PS nanowires to the side of CdS with an optical fiber probe; c) injecting chloroform vapor; and d) dissolving and rearranging the PS nanowires into a polymer spindle.

[0028] Figure 3This is an electron microscope image of the polymer composite semiconductor micro / nano laser of the present invention;

[0029] Figure 4 This is an example of the fabrication of the liquid crystal composite semiconductor micro / nano laser of the present invention, wherein a is the formation of a droplet by a pipette, b is the contact between the droplet and the nanowire, c is the transfer of the liquid crystal droplet to the nanowire, and d is a composite structure diagram under an optical microscope;

[0030] Figure 5 The images shown are optical microscope images of the liquid crystal composite semiconductor micro / nano laser of the present invention, where a is a bright field image of the non-spindle body, b is a dark field image of the non-spindle body, c is a bright field image of the composite structure, and d is a dark field image of the composite structure.

[0031] Figure 6 The images shown are electron microscope (EM) images of polymer composite CdS lasers of different sizes according to the present invention. In the images, a represents spindles of different sizes on the same nanowire, b represents an EEM image of a spindle obtained when the PS line is 4 μm, c represents an EEM image of a spindle obtained when the PS line is 6 μm, and d represents an EEM image of a spindle obtained when the PS line is 8 μm.

[0032] In the figure: 1. Semiconductor micro / nanowires; 2. Suspension support structure; 2. Substrate; 202. Mesh support structure; 201. Polymer spindle; 3. Fiber optic probe; 4. Syringe; 5. PS microwires; 6. Pipette; 7. 5CB liquid crystal; 8. Liquid crystal spindle coating structure; 9. Detailed Implementation

[0033] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0034] Example 1:

[0035] See Figures 1 to 6 A method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser includes the following steps:

[0036] Step 1) Based on micro-nano manipulation under a microscope, a single semiconductor micro / nanowire 1 is partially suspended and fixed on the suspension support structure 2.

[0037] Step 2) Using the fiber optic probe 4 that moves precisely in three-dimensional space, the polymer / liquid crystal is placed at a predetermined position on the semiconductor micro / nanowire 1.

[0038] Step 3) Using an optical fiber probe 4, liquid polymer / liquid crystal droplets are slid along the axial direction of the semiconductor micro / nanowire 1, so that the polymer / liquid crystal droplets form one or more polymer spindles 3 on the semiconductor micro / nanowire 1 under the driving force of surface tension and Rayleigh instability.

[0039] Example 2:

[0040] The main structure of this embodiment is the same as that of embodiment 1. Further, in step 1), the semiconductor micro / nanowire 1 generates spontaneous or stimulated emission under optical pumping conditions and is amplified.

[0041] The suspension support structure 2 includes a base 202 and a mesh support structure 201 arranged on the base 202.

[0042] Example 3:

[0043] The main structure of this embodiment is the same as any one of embodiments 1 to 2. Further, in step 2), if the polymer / liquid crystal solidifies within time T, solvent vapor for dissolving the polymer / liquid crystal is introduced into the assembly area through syringe 5.

[0044] Example 4:

[0045] The main structure of this embodiment is the same as any one of embodiments 1 to 3. Further, in step 3), during the formation of the polymer spindle 3, the transverse diameter and axial length of the polymer spindle 3 are adjusted by controlling the volume of the polymer / liquid crystal material.

[0046] Example 5:

[0047] The main structure of this embodiment is the same as any one of embodiments 1 to 4. Furthermore, the polymer spindle 3 is a microcavity structure that is thick in the middle and gradually thins at both ends, forming a whispering-gallery mode, which constrains the light field in the cross-sectional direction and axial direction of the semiconductor micro / nanowire 1, and propagates cyclically along the cavity of the microcavity structure.

[0048] Example 6:

[0049] The main structure of this embodiment is the same as any one of embodiments 1 to 5. Further, in step 3), when using a liquid polymer, the step of forming one or more polymer spindles 3 on the semiconductor micro / nanowire 1 includes:

[0050] Using an optical fiber probe 4, polymer microwires are picked up from the liquid polymer and brought into contact with semiconductor micro / nanowires 1.

[0051] Solvent vapor is introduced into the environment where the semiconductor micro / nanowire 1 is located and acts on the polymer microwire to soften the polymer microwire.

[0052] The softened polymer microwires spontaneously rearrange and shrink along the axial direction of the semiconductor micro / nanowire 1, and self-assemble on the semiconductor micro / nanowire 1 to form a coating structure with spindle-shaped geometric features, thereby forming one or more polymer spindles 3 on the semiconductor micro / nanowire 1.

[0053] Example 7:

[0054] The main structure of this embodiment is the same as any one of embodiments 1 to 6. Further, in step 3), when liquid crystal is used, the step of forming one or more polymer spindles 3 on the semiconductor micro / nanowire 1 includes:

[0055] Liquid crystal was introduced onto the surface of semiconductor micro / nanowire 1 using a micropipette 7.

[0056] Withdrawing the pipette 7, under the combined effect of nanowire curvature, suspended geometric constraints, and interface energy minimization, the liquid crystal material evolves into a localized liquid crystal droplet structure attached to the surface of the nanowire, thereby forming one or more polymer spindles 3 on the semiconductor micro / nanowire 1.

[0057] Example 8:

[0058] The laser obtained according to any one of the preparation methods in Examples 1 to 7 is a micro / nano laser with semiconductor micro / nano wires 1 as the gain medium and polymer spindle 3 as the resonant cavity.

[0059] Example 9:

[0060] The main structure of this embodiment is the same as that of embodiment 8. Furthermore, when the stimulated emission gain obtained by the light during the round-trip propagation process in the polymer spindle 3 exceeds the cavity loss, a specific longitudinal mode is preferentially amplified and forms a stable oscillation, and laser radiation is output at the interface between the polymer spindle 3 and the air.

[0061] Example 10:

[0062] The main structure of this embodiment is the same as any one of embodiments 8 to 9. Furthermore, when the laser is working, when the light propagates to the region of the polymer spindle 3, the abrupt change in refractive index between the polymer / liquid crystal and air causes some of the laterally propagating light to undergo total internal reflection at the sidewall of the semiconductor micro / nanowire 1, forming a lateral light field confinement.

[0063] Meanwhile, in the axial direction, the polymer spindle structure 3 introduces an equivalent focusing effect, causing the beam inside the cavity to continuously converge during the round-trip propagation process, forming a longitudinal optical field constraint.

[0064] Example 11:

[0065] The present invention aims to provide a functional polymer / liquid crystal composite semiconductor micro / nano laser and its fabrication method, which has the characteristics of low laser threshold, high optical stability and flexible functionalization.

[0066] The technical solution adopted to achieve the technical objective of this invention is as follows: a functional polymer / liquid crystal composite semiconductor micro / nano laser and its fabrication method, comprising the following steps:

[0067] 1) Using micro-nano manipulation under a microscope, a single semiconductor micro-nanowire is partially suspended and fixed on a substrate with micropores or microgrooves.

[0068] 2) Using micro-nano probes that can move precisely in three-dimensional space, polymers or liquid crystals with a length of tens of micrometers can be placed at predetermined positions on semiconductor micro-nano wires.

[0069] 3) In step two, if the polymer / liquid crystal solidifies rapidly within ten minutes during the transfer process or after being transferred to the predetermined position of the semiconductor micro / nanowire, solvent vapor capable of dissolving the polymer / liquid crystal can be introduced into the assembly area through a capillary tube to readjust its morphology; if the polymer / liquid crystal in step two can remain liquid within ten minutes, this step can be omitted.

[0070] 4) By using micro-nano probes to slide liquid polymer / liquid crystal droplets along the axis of micro-nano wires, a spindle-shaped microcavity structure with a thickened middle and thinned ends is formed on the outside of the micro-nano wires under the driving force of surface tension and Rayleigh instability. This constructs a whispering-gallery mode optical microcavity, which strongly confines the light field in both the cross-sectional direction and the axial direction of the micro-nano wires and allows it to propagate cyclically along the cavity.

[0071] 5) The transverse diameter and axial length of the polymer spindle 3 are adjusted by controlling the volume of the polymer / liquid crystal material. There is a corresponding relationship between the volume of the polymer / liquid crystal material and the final size of the polymer spindle 3. Generally, under basically the same experimental conditions, as the volume of the polymer / liquid crystal material increases, the overall size of the polymer spindle increases accordingly, and its transverse diameter and axial length also increase; when the material volume decreases, the size of the spindle decreases accordingly, and its transverse diameter and axial length also decrease.

[0072] 6) Under optical pumping conditions, spontaneous or stimulated emission is generated and amplified in the semiconductor micro / nanowires. When light propagates to the spindle region, the abrupt change in refractive index between the polymer / liquid crystal and air causes some of the laterally propagating light to undergo total internal reflection at the sidewalls of the micro / nanowires, thereby achieving lateral optical field confinement. Simultaneously, in the axial direction, the spindle structure acts like a curved mirror, introducing an equivalent focusing effect, causing the beam within the cavity to continuously converge during its round-trip propagation, forming a stable longitudinal optical field confinement. Through the above-mentioned synergistic confinement mechanism of lateral and longitudinal directions, beam divergence and lateral radiation leakage are effectively suppressed, the mode volume is reduced, and the intracavity optical field intensity and the quality factor of the resonant cavity are significantly improved.

[0073] 7) When the stimulated emission gain obtained by light during its round-trip propagation within the cavity exceeds the cavity loss, a specific longitudinal mode is preferentially amplified and forms a stable oscillation, ultimately outputting laser radiation with high coherence, high brightness, and narrow linewidth characteristics at the interface between the spindle and air. By controlling the length, diameter, refractive index distribution, and surface environment of the micro / nanowires and the spindle, the laser threshold, mode, and wavelength can be further adjusted.

[0074] Example 12:

[0075] An embodiment of the fabrication of a polymer-composite CdS semiconductor micro / nano laser. In this embodiment, the semiconductor micro / nanowire 1 is selected as a CdS single-crystal micro / nanowire with a diameter of 800–1000 nm and a length of 10–30 μm. The micro / nanowire is obtained by chemical vapor deposition and used as the laser gain medium. The functional polymer is selected as polystyrene (PS), which has good optical transparency, low optical loss, and stable chemical properties, making it suitable for constructing whispering-gallery mode microcavity structures. The solvent vapor used is chloroform vapor. The substrate is selected as a fused silica microchannel array structure substrate. Specific steps are as follows (e.g.) Figure 2 (as shown)

[0076] 1) High-quality, smooth-surfaced, and uniformly sized CdS semiconductor micro / nanowires were prepared by chemical vapor deposition. After preparation, a micro / nano system consisting of an optical microscope and a fiber optic probe was used to precisely manipulate individual target CdS micro / nanowires, transferring and positioning them in a predetermined region of the microchannel. This created a locally suspended structure between two support points, reducing optical losses introduced by the substrate and providing geometric freedom for subsequent polymer rearrangement.

[0077] 2) After the micro-nanowire suspension is completed, a thin PS microwire 6 is picked from the pre-fabricated polystyrene (PS) microwire using an optical fiber probe through the same micro-nano system, and accurately placed at the designated position of the CdS micro-nanowire so that the PS microwire and the surface of the micro-nanowire form initial contact.

[0078] 3) Subsequently, while keeping the sample stationary, a small amount of chloroform vapor is slowly introduced into the surrounding environment using a syringe 5 or a micro-gas introduction device. The chloroform vapor is injected into and acts on the PS microwires 6 in a localized area, causing solvent-induced local softening and simultaneously generating significant interfacial wetting behavior on the CdS micro / nanowire surface. Under the combined influence of Rayleigh instability and the geometric constraints of the micro / nanowires, the softened PS material undergoes spontaneous rearrangement and contraction along the micro / nanowire axis, gradually evolving towards the lowest energy state, and ultimately self-assembling in specific regions of the micro / nanowires to form a coating structure with spindle-shaped geometric features.

[0079] 4) By precisely controlling the introduction rate of chloroform vapor, the reaction time, and the initial length and diameter of PS microwires 6, the length, maximum diameter, and structural symmetry of the spindle can be adjusted. When the chloroform vapor supply is stopped, the PS solidifies rapidly with the evaporation of the solvent, and the resulting spindle composite structure remains stable on the surface of the micro- and nanowires.

[0080] Typical electron micrographs of the prepared composite structure are shown below. Figure 3 As shown, the CdS micro / nanowires maintain a well-defined linear morphology with a smooth surface and uniform diameter. A clearly structured and geometrically stable polymer spindle-shaped coating structure is formed at specific locations on the micro / nanowires. The spindles are symmetrically distributed along the axis of the micro / nanowires, closely adhering to them. The interface is continuous, and no obvious cracks or peeling phenomena were observed, indicating that the polymer can effectively wet and spontaneously rearrange on the micro / nanowire surface under the action of solvent vapor. The spindle region exhibits a smooth curved contour, with the maximum diameter located at the center of the structure, gradually transitioning to the micro / nanowire body at both ends, resulting in a uniform overall morphology. This method enables the controllable construction of polymer spindle composite microcavity structures while maintaining the original high-quality crystal morphology of CdS micro / nanowires.

[0081] Example 13:

[0082] An example of fabrication of a liquid crystal composite CdS semiconductor micro / nano laser. In this example, the selected semiconductor micro / nanowires and substrate types are consistent with those in Example 12. The liquid crystal material is a room-temperature nematic liquid crystal 4-cyano-4'-pentylbiphenyl (5CB), which is liquid at room temperature and has high optical anisotropy, good fluidity, and low optical absorption loss, making it suitable for the construction and control of micro / nano optical cavity structures.

[0083] The preparation and suspension methods of the CdS micro / nanowires are the same as in Example 12. Subsequently, liquid 5CB is precisely introduced onto the surface of the CdS micro / nanowires using a micropipette method. The specific steps are as follows (e.g.) Figure 4 (as shown)

[0084] 1) A small amount of 5CB liquid crystal 8 is preloaded into a glass micropipette 7, which is made of glass capillary and has an inner diameter of approximately 1–3 μm at the tip. The micropipette 7 is fixed on a triaxial micromanipulation platform. Under real-time observation with an optical microscope, the position of the micropipette 7 is slowly adjusted so that the tip gradually approaches the suspended region of the semiconductor micro / nanowire 1 (CdS micro / nanowire).

[0085] 2) When the tip of the pipette is approximately 1–2 μm away from the nanowire, a micro-scale liquid crystal droplet is formed at the tip of the pipette 7 by controlling a small amount of positive pressure. The micromanipulation platform is then finely adjusted to allow the liquid crystal droplet to make slight contact with the surface of the CdS micro / nanowire. At the moment of contact, liquid 5CB spontaneously transfers from the tip of the pipette 7 to the surface of the CdS micro / nanowire under the influence of surface wetting and capillary forces, and then locally spreads and aggregates along the nanowire axis.

[0086] 3) Subsequently, the pipette 7 is slowly withdrawn. Under the combined effects of nanowire curvature, suspended geometric constraints, and minimization of interfacial energy, the liquid crystal material gradually evolves into a localized liquid crystal droplet structure attached to the nanowire surface. By controlling the liquid crystal volume at the tip of the pipette 7, the contact position, and the contact time, precise control over the size and spatial distribution of the liquid crystal droplets can be achieved.

[0087] 4) After completing the liquid crystal transfer, the sample was placed in a room temperature environment to allow the liquid crystal structure to stabilize. The formed liquid crystal composite microcavity structure showed a clear liquid crystal outline under a microscope. The liquid crystal droplets were stably attached to the surface of CdS micro / nanowires, and no obvious loss or morphological collapse was observed. This indicates that the microfluidic transfer method can achieve reliable composite of liquid 5CB and semiconductor micro / nanowires without introducing significant mechanical disturbance.

[0088] Typical optical microscope images of the prepared liquid crystal composite structure are shown below. Figure 5 As shown, by comparing the bright and dark field optical images before and after the composite process, it can be seen that a liquid crystal spindle coating structure with a clear structure and stable geometric morphology was formed on the CdS micro-nanowires through micromanipulation.

[0089] Example 14:

[0090] An embodiment of the fabrication of a polymer composite semiconductor micro / nano laser with controllable size adjustment. Based on the fabrication method of polymer spindle 3 composite CdS micro / nanowire structure described in Example 12, this embodiment conducts a systematic control experiment on the volume of polymer spindle 3 to further verify the controllability and repeatability of the spindle geometry of this method.

[0091] In the specific implementation process, the preparation and suspension method of CdS micro / nanowires were the same as in Example 12. Using a micromanipulation needle, three segments of PS microwires with initial diameters of approximately 2 μm and initial lengths of 4.6 μm, 6.4 μm, and 9.8 μm (corresponding to volumes of 14.4 μm³, 20.1 μm³, and 30.8 μm³) were picked from the pre-fabricated polystyrene (PS) microwires and accurately placed at designated suspension positions on the CdS micro / nanowires, ensuring stable initial contact between the PS microwires 6 and the nanowire surface. The resulting spindle axial lengths were approximately 3.7 μm, 3.8 μm, and 5.0 μm, and the maximum transverse diameters were approximately 2.2 μm, 2.6 μm, and 2.8 μm, respectively. While maintaining other experimental conditions, the transverse diameter and axial length of the spindle were pre-controlled by systematically changing the initial length and initial diameter of the PS microwires 6, such as... Figure 6 As shown.

Claims

1. A method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser, characterized in that, Includes the following steps: Step 1) Based on micro-nano manipulation under a microscope, a single semiconductor micro-nano wire (1) is partially suspended and fixed on a suspension support structure (2); Step 2) Using a fiber optic probe (4) that moves precisely in three-dimensional space, the polymer / liquid crystal is placed at a predetermined position on the semiconductor micro / nanowire (1); Step 3) Using an optical fiber probe (4), liquid polymer / liquid crystal droplets are slid along the axial direction of the semiconductor micro / nanowire (1) to form one or more polymer spindles (3) on the semiconductor micro / nanowire (1) under the influence of surface tension and Rayleigh instability.

2. The method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser according to claim 1, characterized in that, In step 1), the semiconductor micro / nanowire (1) generates spontaneous or stimulated emission under optical pumping conditions and is amplified; The suspension support structure (2) includes a base (202) and a mesh support structure (201) arranged on the base (202).

3. The method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser according to claim 1, characterized in that, In step 2), if the polymer / liquid crystal solidifies within time T, solvent vapor for dissolving the polymer / liquid crystal is introduced into the assembly area via syringe (5).

4. The method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser according to claim 1, characterized in that, In step 3), during the formation of the polymer spindle (3), the transverse diameter and axial length of the polymer spindle (3) are adjusted by controlling the volume of the polymer / liquid crystal material.

5. The method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser according to claim 4, characterized in that, The polymer spindle (3) is a microcavity structure that is thick in the middle and gradually thins at both ends, forming a whispering mode. This constrains the light field in the cross-sectional direction and axial direction of the semiconductor micro / nanowire (1) and allows it to propagate cyclically along the cavity of the microcavity structure.

6. The method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser according to claim 1, characterized in that, In step 3), when using a liquid polymer, the step of forming one or more polymer spindles (3) on the semiconductor micro / nanowire (1) includes: Using an optical fiber probe (4), polymer microwires are picked up from the liquid polymer and brought into contact with semiconductor micro / nanowires (1); Solvent vapor is introduced into the environment where the semiconductor micro / nanowire (1) is located and acts on the polymer microwire to soften the polymer microwire; After softening, the polymer microwires undergo spontaneous rearrangement and contraction along the axial direction of the semiconductor micro / nanowire (1), and self-assemble on the semiconductor micro / nanowire (1) to form a coating structure with spindle-shaped geometric features, thereby forming one or more polymer spindles (3) on the semiconductor micro / nanowire (1).

7. The method for fabricating a functional polymer / liquid crystal composite semiconductor micro / nano laser according to claim 1, characterized in that, In step 3), when using liquid crystal, the step of forming one or more polymer spindles (3) on semiconductor micro / nanowires (1) includes: Liquid crystal was introduced onto the surface of semiconductor micro / nanowires (1) using a micropipette (7); Withdraw the pipette (7), and under the combined effect of nanowire curvature, suspended geometric constraints and interface energy minimization, the liquid crystal material evolves into a local liquid crystal droplet structure attached to the surface of the nanowire, thereby forming one or more polymer spindles (3) on the semiconductor micro / nanowire (1).

8. The laser obtained by any one of the preparation methods according to claims 1-7, characterized in that: This laser is a micro / nano laser with semiconductor micro / nano wires (1) as the gain medium and polymer spindles (3) as the resonant cavity.

9. The laser according to claim 8, characterized in that: When the stimulated emission gain obtained by light during the round-trip propagation within the polymer spindle (3) exceeds the cavity loss, a specific longitudinal mode is preferentially amplified and forms a stable oscillation, outputting laser radiation at the interface between the polymer spindle (3) and air.

10. The laser according to claim 8, characterized in that: When the laser is working, when the light propagates to the region of the polymer spindle (3), the abrupt change in refractive index between the polymer / liquid crystal and air causes some of the transversely propagating light to undergo total internal reflection at the sidewall of the semiconductor micro / nanowire (1), forming a transverse light field constraint. Meanwhile, in the axial direction, the polymer spindle (3) structure introduces an equivalent focusing effect, which causes the beam in the cavity to continuously converge during the round-trip propagation process, forming a longitudinal optical field constraint.

Images