Chip-based nanolasers are devices that use optical components that are integrated onto a chip. There are several kinds of chip-based nanolasers, such as LSP, SPP, and Photonic crystal nanolasers.
Integrated optical devices on a chip
Integrated optical devices on a chip offer a promising alternative to electronic integrated devices. Its advantages include eliminating heat generation, reducing the size and operating costs, and speeding up processing. These features are important for applications in data centers, medical applications, and Internet of Things (IoT) technologies.
The high density of nanolasers could help speed the expansion of the IoT. They could also support big data analytics and improve data transport across the internet. In addition, they could enable the streaming of ultrahigh-definition movies and interactive online encounters. With continued progress, they may even accelerate the expansion of the Internet of Things.
Scientists in Korea have developed a new optical approach to nanolasers. Rather than using electrodes for each laser, they have instead employed a special optical driver that generates programmable light patterns through interference. This driver is then able to drive several nanolaser arrays by simply running one optical fiber.
Researchers have also shown that the polarization and propagation direction of a pump beam can be changed to drive different light patterns. However, these patterns must be perfectly aligned with the nanolaser arrays. To do this, they adjusted the polarization of the pump beam and the phase of the lasers.
Using these approaches, researchers have been able to create photonic crystal nanolasers. These were arranged on an optical microfiber with a diameter of two microns. Once they were in place, they were programmed with an interference pattern. Unlike previous approaches, this one relied on a highly accurate transfer printing method.
In the future, scientists believe the ability to effectively drive and regulate nano-sized light sources could open up new opportunities in signal processing. Specifically, they believe that efficient control of these light sources can enable faster information processing at lower powers.
Recent developments in this field are set to break down roadblocks in the development of nanolasers. For example, these nanolasers may eventually be used in the future of optical integrated circuits. Moreover, they are expected to lead to a number of new opportunities for research in other areas, including biosensing and optical communications.
Although the concept of on-chip integrated optical devices is still relatively new, it is expected to significantly cut down on manufacturing and operating costs. Moreover, the isolation ratio of the integrated optical isolator has been measured to be greater than 60 dB.
LSP-based nanolasers
LSP-based nanolasers are nanoscale optical devices that transmit information using light. These lasers can be used in a variety of applications including nanolithography, optical interconnections and data storage. They can also be used for biomedical applications.
A number of different designs have been investigated for the development of SPP nanolasers in the past decade. Although these designs all share similarities, the performance of each is distinct. Because of the small physical size of the nanolaser, the output power is low. However, the devices have a high potential for improving the performance of integrated circuits. In particular, they are expected to be superior to transistor-based interconnecting systems.
Although most research on LSP-based nanolasers has been conducted in ensembles of metal nanostructures, it is possible to use other types of structures. For example, researchers have developed photonic crystal nanolasers that are applied to optical fibers. Photonic crystals have a very thin insulating layer, which allows for better bandwidths.
Other approaches to constructing these devices involve the use of metal nanostructures that confine photons to a metallic surface. This reduces the plasmonic loss. Some of the metals that exhibit the lowest losses include silver, copper, and gold. It is important to design a structural parameter that maximizes the confinement factor.
The gain saturation effect also has an effect on the speed of modulation. As the pumping power increases, the resonance becomes suppressed. To counter this, researchers have developed a technique that uses an external optical pump to excite the SPs. This is known as a gain-assisted SPR sensor.
The advantages of this structure include the ability to create programmable patterns of light via interference. Additionally, the use of photons instead of electrons minimizes transmission loss and energy consumption.
However, these devices require significant on-chip space and electricity for electrodes. These are both difficult to fabricate at the nanoscale. Thus, it is expected that a practical SPP laser requires a very low Q-factor and a relatively small device footprint.
Another promising class of LESPR sensors involves the use of gap plasmon modes. This type of sensor can significantly increase the sensitivity of the device. Therefore, it is worth exploring.
Photonic crystal nanolasers
Photonic crystal nanolasers are chip-based light sources that operate at wavelengths below one meter and have a very high modulation rate. They have been demonstrated to have a lot of potentials. But to effectively drive and regulate these miniature light sources, new techniques are needed. Here, scientists in Korea present a new optical approach to achieving this goal.
Researchers used a transfer printing process to fabricate photonic crystal nanolasers. The devices were positioned at 18 microns apart and worked at wavelengths of 1535 nm. These arrays can be driven and programmable by a special optical driver. This is a breakthrough in optical communication.
Typically, electrode pairs are used to form nanolaser arrays. However, the use of electrodes requires significant chip space and can slow processing. For this reason, researchers decided to replace the electrodes with a special optical driver.
After adjusting the polarization of the pump beam, they were able to program the driving of multiple nanolasers in a single fiber. In the same way, they were able to program the interference pattern of the pump beam to control the light patterns of the arrays. As a result, the mode volumes were small, which allowed for greater light-matter interactions at the single-photon level.
By comparing the pumping schemes, the researchers were able to determine the limiting factors on efficiency. Their results suggested that the asymmetric out-of-plane index introduces optical loss in the photonic crystal cavity. Consequently, the size of the mode volume should be reduced. Moreover, the phase of the pump beam should be adjusted.
Researchers also studied the impact of the disorder on the Q-factor of the nanolasers. This is an important factor for the development of ultra-low power consumption nano-lasers. Therefore, researchers used a numerical simulation to investigate the effect of the disorder. It was found that the Q-factor increased by 10 mW for every p-doping increase.
These photonic crystal nanolasers were placed on a two-micron-diameter optical fiber. Their photoresponsivity was 8.8 mA/W. They were also operated at room temperature. Aside from their great performance, the researchers found that these devices could be transferred to a non-native substrate with little difficulty.
SPP nanolasers
SPP nanolasers are chip-based optical devices that emit coherent light on the nanoscale. They can be used for optical interconnections and data storage. These lasers are based on the interaction of photons with surface plasmons.
Compared with conventional lasers, nanolasers are smaller, faster, and more power-efficient. This enables their use in sensing and biomedical applications. But the small size of these devices also makes them susceptible to the effects of ambient refractive index changes. For practical purposes, SPP nanolasers require low thresholds and a high Q-factor. In addition, these devices must be compatible with silicon-based platforms. Hence, they are likely to be better than transistor-based interconnecting systems.
There are two types of plasmonic nanolasers: localized surface plasmons (LSPs) and surface plasmon polaritons (SPPS). LSPs are generated by electromagnetic fields, while SPPS are induced by conducting electrons.
During the last decade, several designs of SPP nanolasers have been demonstrated. A typical SPP wavelength range is between 10 nm and 100 nm. The modulation speed is in the region of a few THz. However, the SPP nanolaser’s performance depends on the ambient refractive index changes and the material properties of the gain medium.
To achieve continuous-wave operation, the insulating layer needs to be designed carefully. In addition, the thickness of the insulating layer is an important design factor. Using different insulating layers will influence the mode size, loss, and mode confinement. It is difficult to find the ideal insulator thickness. Nevertheless, it is important to choose the insulator thickness with the most suitable loss-to-confinement ratio.
Besides, SPP nanolasers are expected to be very useful in high-speed optical communications. They are expected to improve the efficiency of integrated circuits and increase the speed of information transmission. Furthermore, they can be used for biomedical applications, such as cell detection and harmful substance detection.
Another advantage of SPP nanolasers is their lower lasing threshold. This makes them desirable for integrated optical interconnects. Moreover, energy consumption is also reduced because the photons are neutral. With the rise of the demand for integrated circuits, people are looking for compact and efficient lasers.
Recently, SPP nanolasers have demonstrated their feasibility in the lab. However, they are still limited by their small size and the lack of a proper wavelength.
