Stretchable and Broadband Cavity‐Free Lasers Based on All 2D Metamaterials

Abstract

all 2D materials, unlike gapless graphene, monolayer transition metal dichalcogenide (TMDC), such as MoS 2 , has attracted considerable attention in electronics, optoelectronics, spintronic applications due to their chiral optical properties, [7,8] relatively high carrier mobility, and tunable bandgap. [9][10][11][12][13][14][15][16] In particular, the unique mechanical flexibility makes TMDC and graphene materials as the most attractive candidates to satisfy the requirement of flexible optoelectronic devices, which are the fundamental building block of wearable technology.The most interesting characteristic of graphene is its conical band structure around the Dirac point, [17] which makes electrons and holes behave as massless Dirac fermions with a Fermi velocity about 10 6 m s −1 . [18] As a result, the nonlinear dynamics of electrons in graphene can achieve band filling transient state via electron collisions and generate Pauli blocking effect. [19] This unique property not only makes graphene as fast saturable absorber over a wide spectral range, which can be applied to passively mode-locked lasers, [20,21] but also leads to transient population inversion, which has a great potential to play a significant role in stimulated emission. [20,22] However, the realization of such remarkable capability is still awaiting for further exploration.Intuitively, by combining the outstanding properties of graphene and 2D MoS 2 to form high-performance devices with unprecedented properties is a natural research guideline. Indeed, the integration of MoS 2 and graphene has been successfully synthesized for wide range applications, such as solar cells, photodetectors, transistors, and biosensors. [23,24] With the success of the discovery of many interesting novel devices based on vertical stacking, 2D nanocomposites have drawn increasing interests. Unfortunately, the study and demonstration of laser devices utilizing the unique properties of 2D nanocomposites are still rather limited until now.Lasers, with higher efficiency and narrow band frequency emission than LEDs, play an important role from scientific research, optical communications, display technology, medicine, to fluorescence microscope, and etc. [25][26][27][28] Two basic elements are necessary for laser operation: gain mediums that can provide light emission and optical cavities that can confine the emitted light. Because of the strong light-matter interactionThe development of two-dimensional (2D) materials has brought the breakthrough for scientific discoveries and widespread applications in many emerging devices. However, the related study on lasers is rather limited. In this study, a stretchable and broadband cavity-free laser device based on all 2D metamaterials consisting of molybdenum disulfide (MoS 2 )/graphene nanocomposites is designed and demonstrated. When the pumping power density of the device is more than 200 W cm −2 , multiple pronounced narrow peaks with linewidth <0.5 nm superimpose on the spectra, providing the signature for laser actions. The op...

Rippled Metallic‐Nanowire/Graphene/Semiconductor Nanostack for a Gate‐Tunable Ultrahigh‐Performance Stretchable Phototransistor

“…In additional, in recent reports, it has been observed that a rippled structure is an excellent matrix for photon trapping, as illustrated in Figure 4f. [ 16,26,46,58 ] As a result, the scattered photons get reabsorbed in the device, diminishing the scattering loss of photons, which in turn contributes to the photoresponsivity and gain.…”

[Retracted] The Study of Midinfrared Extremely Narrow Dual‐Band Absorber Based on a Novel Metamaterial Structure

“…The detector can also be used for flammable, toxic, and harmful gases such as CH 4 , CO, and C 2 H 6 in the midinfrared region and SO 2 F 2 and SF 6 in the far-infrared [28]. It can also be used in thermal imaging [29], hyperspectral imaging [30], meteorology [31], free-space light [32], communication [33], remote sensing [34], and lasers [35] and for identifying biological compounds [36].…”

Strain Modulation of Optoelectronic Properties in Nanolayered Black Phosphorus: Implications for Strain-Engineered 2D Material Systems

“…These difficulties mainly arise as the electrodes used to inject charge carriers into the 2D semiconducting channel often consist of metal thin films, which break when the strain applied to the film is above 5% . To alleviate this issue, there have been previous works in which prestretched PDMS is able to maintain the integrity of the contact electrodes, while instigating compressive strain onto 2D materials, forming a rippled structure. ,,, Although this is a viable method to study the effects of uniaxial strain on BP, there are still limited studies on the effects of strain on the optoelectronic properties of BP, as these works were focused solely on the optical or electrical properties, respectively. , …”