对下面的英文进行学术润色：System diagram is shown in Fig. 1. Our microscope applied an 80 MHz femtosecond laser (Chameleon Discovery, Coherent) as the excitation source. We use a Pockels cell (Pockels cell: 350-80-LA, Controller: 302RM, Conoptics, Inc.) to adj...-Go服务器开发

The system diagram presented in Figure 1 shows the experimental setup of our microscope, which employs an 80 MHz femtosecond laser (Chameleon Discovery, Coherent) as the excitation source. To control the total energy reaching the sample, we employ a Pockels cell (Pockels cell: 350-80-LA, Controller: 302RM, Conoptics, Inc.). A half-wave plate (AHWP05M-980, Thorlabs) and a polarization beam splitter (CCM5-PBS202/M, Thorlabs) are placed after the Pockels cell to adjust the excitation power between different beamlets. To adjust the width and convergence of beamlets before entering the polarization beam splitter, a custom-made 2x beam expander (AC254-200-B and ACN254-100-B, Thorlabs) is employed.

After passing through the polarization beam splitter, one of the two resulting beamlets undergoes a 6.25 ns time delay relative to the other using a 50:50 beam splitter (GCC-403121, Daheng), thereby producing four distinct beamlets with time delays of 0 ns, 3.1 ns, 6.2 ns, and 9.3 ns respectively. These four beams are combined by a pickup mirror (PFD10-03-P01, Thorlabs), yielding beamlets with identical propagation direction but distributed in square positions. The diameter of these resultant beams is then adjusted by an adjustable reverse-placed beam expander (BE02-05-B,Thorlabs) so as to match that of subsequent scanning galvanometer pair (8315K & CRS8 kHz,Cambridge Technology).

These four synchronized beams are then relayed onto the back focal plane of an objective lens (CFI75 LWD16X W/NA0.8/3mm working distance/16x magnification, Nikon) through a scan lens (SL50-2P2, Thorlabs) and tube lens (TTL200MP2, Thorlabs) pair. Due to deviation from the optical axis, each of the beams forming the two-photon focus behind the objective lens will have different tilt angles. By utilizing this information, we are able to recover three-dimensional distribution information of samples within a certain depth range.

The fluorescence signals generated by the excitation path are reflected by a long-pass dichroic mirror (DMLP805R, Thorlabs), then collected and converged by a lens pair (#49-284, Edmund; KPA034-C, Newport). After filtering by a multiphoton shortpass laser dichroic (ZT775sp-2p-UF1, Chroma) and a green filter (FF03-⁵²⁵⁄₅₀-30-D,Sermock), these signals are detected by a photomultiplier tube (H10770PA-40, Hamamatsu). The gathered fluorescence signal is first amplified by a high-speed current amplifier (DHPCA-100,Femto), then split into four channels using power splitters (ZAPD-30-S+, MiniCircuits).

Three of these channels are connected via cables of varying lengths to achieve 3.1 ns, 6.2 ns and 9.3 ns time delays relative to the 0 ns channel. To ensure that fluorescence signals are collected at the peak, we adjust the length of the 80 MHz laser sampling clock cable as well. The system is controlled by ScanImage 2018 software.

Although there may be some residual signal crosstalk between channels due to limitations in fluorescence lifetime and bandwidth of current amplifier, it is linear and relatively stable. Hence we employ linear demixing schemes to eliminate this crosstalk.